Well, it seems I�ve stalled long enough and decided to tackle the rear end conversion on my �87 VFR. Some of you astute listers may recall the front-end conversion that I tackled a few months ago (Sadly, the thread detailing it seems to have gone missing sad.gif ). In any case, I�m hoping this thread can serve as a bit of a guide for all those looking to fit radials to their first gen VFRs and also to get feedback, opinions and ideas from any who care to offer them.
First some details: My current set up is a YZF600 front end and the stock rear end. The bikes current set-up is a considerable improvement over stock in front-end compliance and feedback as well as in braking. To be honest, in the 3000 miles of moderate street riding I�ve done since the conversion, I�ve never had any issue with the stock rear end � I�m running a bias-ply Dunlop GT501 in the stock size (130/80/18) and my stock rear shock is in good health. Combined with the radial Metz M3 I�m running up front, I�ve never had an issue with available grip or experienced any sort of instability or odd handling that might be attributable to the mismatched tires� I�ve scrubbed the rear tire to the edges and dragged pegs with this combination. However, the possibility of an upcoming track day this fall has me wanting to outfit the bike in matching track-worthy rubber, so radials front and rear it is.
The most common rear end upgrade for the 1st gens is the CBR600 F2/F3 swap, which gives you a sleek 5 spoke 4.5/5 inch rim to run a 160/70-17 rear and to match the F2/F3 front end swap. I�ve decided to go a different route, since I�d like to try and match the rear to the 3 spoke YZF front rim. Considerably less has been written about fitting a wider 3 spoke rear to the VFR, so this stands to be more of a trial and error process than your standard F2 swap.
The rim I�ve chosen to adapt is one from a �90 Honda CBR1000F. It�s a 17 inch, 3 spoke, 5.5 inch wide rim, so it promises to press the limits of what can be made to fit in the relatively narrow VFR swingarm.
[image: IPB Image] '90 CBR1000F rim w/180 tire
It�s a close enough match for the YZF front, and while considerably rarer than the F2/F3 rims (on e-bay anyhow) they tend to be in lesser demand as well. I�ve managed to contact and pick the brains of a couple of folks who�ve done versions of this conversion so have got an idea of what I�m in for, it�s just a matter of the specifics.
A primer before pic:
[image: IPB Image] Rear view before: Skinny bias-ply 130 Rear view before the upgrade: Stock 130/80/18 bias ply on 3.5 inch rim.
Now�.it�s off to the garage to tear apart the rear of the bike and do some measurin� an figurin� comp13.gif
Now�.it�s off to the garage to tear apart the rear of the bike and do some measurin� an figurin� comp13.gif
Stay tuned....
You're most definetly going to have to fab a completely new brake torque arm and space it considerably outward of where the stocker sits.
With "only" a 4.5x17 rim and a 160 michelin, I had to trim the stock brake arm from a ][ to a [ shape right at the leading edge of the tire.
Maybe even look at relocating the caliper to the 6 o'clock position and fabbing a new torque arm to a welded mount on the underside of the swingarm. Heim joints are great for this sort of stuff. Try these guys: http://bulletproofsteering.com/rodendspecs.html
If you find problems with the 180 tire fouling the chain run, you might want to look at a 170/60-17 instead. That'll be plenty of tire. The '90-'93 Viffers came with a 5.5" rear wheel and a 170 tire as stock fitment.
I�ve had a chance to make some measurements and do some preliminary test fitting. Dez Chand was kind enough to hook me up with the details of his CBR1KF swap, so I had his recommendations to work from beer.gif . I�ve gone through the measurements numerous times and feel I have the start to a workable plan.
What I�m gonna need:
1) �90 CBR rim � found this on e-bay, but most year CBR1000F rims from �89 through �96(?) should work. The rear rotor sizes vary between the pre-LBS and LBS models but otherwise I believe they are comparable. I picked the �90 because it�s in great shape and it came in white � the colour I wanted.
2) CBR sprocket/hub assembly with cush drive � bought this with the wheel. Some machining of this hub is required. In stock form the hub/wheel assembly won�t fit between the swingarm so some mods are required. The sprocket carrier mounting faces have to be machined down 10 mm. This is to maintain proper sprocket alignment. You�ll also have to lose the dust seal on the outer sprocket carrier bearing, since the lip (against which the seal sits) needs to be machined down 5mm to allow the whole assembly to fit in the swingarm. (Pics to follow!) I�ll also likely have to ground off the tips of each sprocket mounting stud for the same clearance reasons. This part here looks the be the most complex part of the swap. A good friend with a giant lathe or well outfitted machine shop would be invaluable here. A machining shop can also handle this operation, but it won�t be cheap.
[image: IPB Image] Prepping the hub for machining - pulling the sprocket studs Here you can see the sprocket carrier mounting faces that need to be machined down, along with the lip (dust seal still in place).
3) Custom spacers � The dimension for these were calculated keeping three things in mind: Wheel centerline � The aim is to keep the front and rear wheels properly aligned Sprocket alignment � Misaligned front and rear sprockets will make short work of the countershaft support bearings and your chain and sprockets themselves. I used the stock swingarm to sprocket distance as my target. Rear rotor/caliper alignment � The goal here is to keep the rotor in the same position as it was with the VFR wheel (so that it will still work with the stock carrier and caliper). Again, I used the stock swingarm to rotor-surface distance as the target. I�m going to be using two spacers � one created from shortening a stock VFR spacer, one will be a custom jobbie. (Dimensions to follow).
4) VFR rotor and brake assembly � I�m pleased to report that the CBR rim has the same rotor bolt pattern as the VFR rim, allowing the (still large) VFR rotor to be used in place of the huge CBR unit. This is one advantage of this swap over the F2/F3 swap � you can use your stock VFR rotor, caliper and caliper carrier sans modifications.
5) Brake torque arm modification � This still needs to be modified. I�m hoping that moving the brake arm to the outboard side of the forward mount, and bending the arm into a slight �S� shape to realign it with the carrier mount will gain me enough clearance for the wider wheel and tire. As Rob mentions above, I may have to resort to grinding the arm down slightly. In the event that I can�t get the stock arm to work, some more thought will be needed here. Thanks for the heim joint lead, Rob, those look like they might be the ticket if I have to go the completely custom route! fing02.gif
6) Tire selection � The rim came with a 180/55/17, but I�m going to be swapping to a 170/60/17 for a couple of reasons. Firstly, as Rob mentions, clearance will be awfully tight with the 180, not only with the swingarm, but with the chain. The by-product of the modifications in #2 above is to bring the sprocket and chain 10mm closer to the centerline of the tire, which means that with the 180 fitted, and proper chain alignment, there will be but a couple of millimeters between the chain and the edge of the tire. Dez Chand ran a 180 on his race bike for 3 seasons with this set-up and didn�t have any issues, but I�d sooner fit a slightly narrower 170 to free up a bit more breathing room. The 170 will also be a slightly taller tire than the 180, which will be a help to minimizing the ride height that I�m losing going to a 17 inch wheel. The 170 promises to still be more than enough tire for the 80 rwhp VFR and it�s spindly swingarm. Those who race the old VFRs tend to prefer the quicker handling of a 160 tire to the 170, and I expect a 180 would slow the handling even further.
7) Ride height � I�m going to need a way of restoring the rear ride height back to stock (or ideally a bit higher, to offset that wide, slow turning rear). This will be accomplished by a shock swap. I have a couple of options here � depending on how much lift I need at the back. A while ago I picked up a cheap CBR1KF shock as well as a Fox TC ride height adjustable shock off of e-bay. I�m still in the process of getting a proper spring and clevis mount arranged for the Fox shock, but I�ll be looking to get that sorted out soon.
For now though, I�ve dropped the hub and spacers off at my machinist�s to have them work their magic. I can't wait to get it back, but I know I've still a bunch more stuff to get sorted in the next few days biggrin.gif
As always, thoughts, comments, criticisms and suggestions always appreciated wheel.gif
I love the look of a first gen with the F2 wheels on it. I think I want to pick one of these bikes up as a project bike if I can find one. So I am following your progress closely.
I love the look of a first gen with the F2 wheels on it. I think I want to pick one of these bikes up as a project bike if I can find one.
I agree that the 5 spokes really compliment these older bikes. If you haven't already, you should check out Rob's '86 F2 conversion (link in sig) - it's one of the cleanest examples of that conversion that I've seen. I'd say go for it - you can never have too many VFRs...besides, then you can own your very own Frankenviffer!
I think I might kidnapp you and lock you in my basement with my bike, and my tools this winter.
As long as you have a well stocked beer fridge and satellite radio, it doesn't sound like such a bad way to pass the winter (heck, it's what I do anyhow goofy.gif ). I fear my bike might miss me though....
I like your approach to the radial upgrade, but I bet that I don't go this route. Just because the F2 swap apprears a good deal easier/cheaper.
I would be curious to hear a ride report on your mods vs. the F2 swap mods. I bet that is a bit of a longshot.
True, the F2 swap is a bit easier (especially the rear wheel swap), since there is less machining involved - although you do have cut and reweld the brake caliper holder to accomodate the smaller F2 rotor. Cost wise though, I think the biggest advantage to the F2/F3 swap is that you can run a taller 160/70/17 tire on both of those rims which allows you to maintain your stock ride height - which means you don't have to spend out on a modified/aftermarket height adjustable shock if you don't want to. As for this swap vs. the F2 swap - I suspect there would be very little between the two configurations when both are properly set-up with sticky rubber and a quality aftermarket shock. Both will likely handle just as well as you could possibly want for the street (and possibly the track....) Hmmm...sounds like there might be an F2 conversion in your future? 491.gif
Pegasus, Aug 30 2006, 10:07 PM Hmmm...sounds like there might be an F2 conversion in your future? 491.gif
Yea, and I got a link from this site a while back for someone that sells all the stuff to do the swap (83-85), no guess work or measurements for me to take that way.
I have even thought about trying to source some chromed wheels (I am REALLY lazy when it comes to cleaning). It hasn't gone past that though. Maybe this winter.?.
How's the rear wheel conversion going there Pegasus?
Are you going to fit taller gearing to compensate for the smaller diameter 17" wheel/tire?
By my calculations, you'll have 4.6% lower gearing with the new 17" wheel and 170/60 tire Vs the stock 18" unit with 130/80 tire, also your stock sprockets are 16/45 for a final drive ratio of 2.8125/1 (from info I gathered on the web).
To get the overall gearing exactly back to stock, you'd need 2.9425/1 gearing, which would roughly equate to a 47 tooth rear with a 16 tooth front, or you could possibly go to a 15 tooth front with a 45 rear.
47/16 would get you 2.9375 which would leave you 1.2% high, and 45/15 would give you 3.000/1 which would be 1.9% low.
OTOH, a 17 front and a 50 rear would be almost exactly correct at 2.9411 which is .0004% higher than stock. comp13.gif
There's an old biker's "rule" (wives tale?) that says the # of teeth front/rear should not be evenly divisible, something about greater chain wear, don't know if that's true or not, but maybe something to consider.....
Sprocketspecialists.com makes anything from 12-18 tooth fronts (VFR) and from 38-71 for the rear (CBR).
....or you could just leave it at 16/45 for more SNAP in every gear. wheel.gif
Uncanny timing VeeferCanuck � I was just about to post about my gearing issue!
With spacers in hand and a freshly machined hub (nice work!) it was time for a test fit! Oops, no wait�..first we have to shorten each of the sprocket mount studs by about 5mm so that they don�t contact the swingarm. One angle grinder, lots of sparks and much metal dust later, we have our completed studs. Install short studs in hub, bolt up sprocket, and Voila!
[image: IPB Image] 180 rear.jpg
But wait....all is not as simple as it appears in radial-land. A number of issues have presented themselves to be pondered:
1) Brake carrier and rotor clearance. I was surprised to find that once the axle-nut was cinched down to spec that outer edge of the rotor was lightly rubbing against part of the caliper carrier bracket. [image: IPB Image] brakecarrier.jpg I can only guess that the spacer that I calculated to fill the wheel/caliper carrier gap (26.5mm) is perhaps a mm too narrow(?). The spacers otherwise seem to work great � when cinched down the spec the wheel spins freely (aside from this), and it�s only a very gentle grazing so they can�t be too far off of ideal. Rather than test this theory with another custom spacer, I took the patented time-honoured approach of many a backyard hack � I took an angle grinder to�er. With the bracket relieved of about 1/8� of an inch of material, there is now plenty of space, still plenty of strength and the rear brake looks to be sorted.
2) The machining of the hub has meant that the chain alignment looks great. However, when the rear wheel is properly aligned (according the marks on the swingarm) the 180 Bridgestone BT020 just grazes the chain. I had been hoping that there might at least a mm or two clearance with the wide 180, but it looks to not be the case, at least with this BT020. I have heard of folks �shaving� the tire edge for clearance, but I�m personally a little bit leary of filing down my tire (Anybody done this? huh.gif ). I�m intending to go to a 170 tire with my next tire change, but had hoped to run the 180 for the shakedown runs until I get the bugs with the conversion worked out.] [image: IPB Image] chainalign.jpg
3a )Ride height. As predicted, I see about a �� at the rear of the bike with the 17 inch rim fitted. On paper it doesn�t sound like much, but when I sat on the bike I was really surprised. It felt really low at the back � like a dog with worms dragging its arse, or one of them blinged-out street drag Suzuki Hay-Bus�s or somesuch thing. goofy.gif
3b ) The CBR1000F rear shock will NOT work. I finally got around to having a good hard look (and a measure) to see if this shock is a real option. As it stands, the shock length is in the ballpark and it has a bottom clevis mount, which would hopefully be fairly easy to adapt, but alas, it�s not. The CBR shock has its preload adjuster mounted at the top of the shock (the stock VFR shock has a remote preload adjuster), and there�s very little room around the upper shock mount (the VFR�s battery box is in the way). My hopes for a cheap solution are dashed. Ah well, back up on Ebay with that one then. On to getting the Fox shock sorted out then. Until this is done, I�ll try adding more preload to the stock rear shock to see what I can gain and likely drop the front forks a bit as well to try and level it out. All though, at 6�2�, I�m not too keen on making the bike any lower. The 170/60 tire should help here slightly too. 4) Brake torque arm � it looks like I�d have to grind an AWFUL lot of metal off of the arm to get it to clear the fat 180, so I�ll likely try and go the bending route. Here�s a pic where I�ve swapped the front mount to the outside of the bracket. I�ll have to bend the arm (benchtop vice and elbow grease?) into a gentle S shape to get it to realign with the rear arm mount. [image: IPB Image] brake arm.jpg
5) Since VeeferCanuck has kindly done all the the difficult calculating for me beer.gif , I�ll skip straight to the point. I was running 15/45 gearing (one down on the front from stock) and have been liking it. I currently have the following sprockets to choose from to get my gearing sorted: 15T, 16T, 42T and 45T. I had originally planned on going 15/42, which (by my calcs, anyhow) would leave me slightly lower than stock, but not as low as the 15/45 I had been running. But�.turns out I�ll have to take a link or two out of my stock 110 link chain to get the chain tensioned properly with this set-up. Not sure yet I want to do this, since this will limit future gearing options. Considering going 15/45, and honing my mad icy-hot stuntin� skillz wheel.gif . Or possibly going back to 16/45�but I come to like the extra SNAP from the 15/45�.Thought required here. As always input welcome. Updates to follow soon�..
There's an old biker's "rule" (wives tale?) that says the # of teeth front/rear should not be evenly divisible, something about greater chain wear, don't know if that's true or not, but maybe something to consider.....
wheel.gif
That rule refers to gears. If the mating gears are exactly divisible one into the other then the same teeth are in mesh each rev of the big gear (wheel). If they are not exactly divisible then the same teeth only come into mesh when the wheel does as many revs as it has teeth; so every 47 revs for a 47 tooth gear wheel. This was particularly relevant with early clocks where the teeth are semi-handmade; by having 'hunting' teeth the wear was evened out & all the teeth got to be the average shape. This was a considerable advantage as it reduced the tight spots. Clocks are really marginal mechanisms (and also intermittent motion as the stop & start every second at the very most) as it is best to use as little weight to drive the pendulum so as to reduce loads and prolong life but tight spots in the gear train cause the clock to stop as soon as the lubricant thickens (and remember the lubricant is only replaced when the clock is serviced; which aint often).
For a chain it is the relationship between chain links & sprocket teeth which determines whether the same links are in mesh. But it really is not important with modern manufacturing as the tolerances are so close nowdays.
Not a whole lot of progress (waiting on the arrival of 170 rear tire), but did manage to get a couple of things sorted. I've managed to suitably modify the brake arm for clearance using nothing more than a bench mounted vice and a few less-than-gentle blows from a rubber mallet. The arm was actually more malleable than I thought it would be. A bit primitive perhaps, but I'm pleased with the results smile.gif
[image: IPB Image] Modded brake arm side view View from the side.
[image: IPB Image] Modded brake arm View from the rear
I also took a pic of the spacers used for this conversion. I've included the dimensions I used, but as always, YMMV.
[image: IPB Image] Stock VFR left, modded VFR center, custom spacer right The stock VFR sprocket side spacer on the left. In the center is a stock spacer thats been machined down to 7 mm. On the right is the custom brake rotor side spacer (20mm ID x 30mm OD x 26.5mm length)
As for the gearing issue, I think I'll leave my 15/45 arrangement for now, for the shakedown runs until I go to install the new rear shock. Wheeee! wheel.gif
Intresting reading here. I find it intresting choosing a cbr 1000f wheel, not a maching yam 600 rear wheel, its norrower at 5,0-17 also. Newermind, intresting anyway. Whell I done a front fork/wheel and rear wheel convension 2 years ago. I used a kawasaki ZX9R usd fork and pvm wheels from a middle 80 gsx-r in 3,5-17 front and 5,0-18 rear. You can se pics of the bike in my gallery. I find it funny that folks have reshaped the rear brake torsion arm from a ][ to a [ to get clarens for F2 convensations. Why? I didn`t have to do it, and got my wheel perfect in center. Well I now have one problem. The pvm wheel is a modular wheel, and now the drive side has come loose. (I didn`t get it loose when I did the covensation for machining it, I had to get it to a shop that had a machin that fitt the whole wheel). Back to the thing, I belive it may have done some damage, not sure how much, havent taken the wheel off yet. If I have to find a new wheel, I cant proberly find a nother used pvm wheel, so I have lookd for dooing a 17" wheel svamp. I on the other hand was leaning for using a Kawasaki ZX6r rear wheel. why, its 5.0 wide and you can use 170/60 and 160/60 tires and has a 3 spoke disign that mach the pvm front I use. The ZX6 use a 525 chain, not a 530 but the vfr750R/RC30 uses a 525 chain and has the same splins on the drive shaft, so its front spocket can be used. As a bonus it pushes the chain line a bit outside for more clearens. Knowin that the oem calliper tuorge arm bends easyly is a good thing.
Intresting reading here. I find it intresting choosing a cbr 1000f wheel, not a maching yam 600 rear wheel, its norrower at 5,0-17 also.
Going with the CBR1000F wheel was a decision I made based partly on precedence, and partly on opportunity. Originally, I'd been contemplating the YZF600 rear, but couldn't track down anyone who had done the swap. And, figuring I didn't have the skills (or patience) to be a pioneer, I was looking for a swap that had been done before. I had managed to find out about a couple of people who'd done the CBR1000F rear swap, and when one turned up cheap on Ebay in the right colour, with everything I'd need....well I took the risk and bought it. I also figured the CBR rim (being a Honda rim from the same era) might also offer additional advantages that would make the details of the swap easier, such as the same axle diameter, brake rotor bolt pattern, and sprocket bolt pattern (allowing me to re-use some VFR parts if needed). I speculate that a 4.5 or 5.0 inch rim would be a better fit for the VFR overall, both for the selection of tires that it offers and ease of fitment, but at the time I couldn't find anyone who'd fitted a 3 spoke wheel in that size.
Whell I done a front fork/wheel and rear wheel convension 2 years ago. I used a kawasaki ZX9R usd fork and pvm wheels from a middle 80 gsx-r in 3,5-17 front and 5,0-18 rear. You can se pics of the bike in my gallery. I find it funny that folks have reshaped the rear brake torsion arm from a ][ to a [ to get clarens for F2 convensations. Why? I didn`t have to do it, and got my wheel perfect in center.
I think it must vary from bike-to-bike. I have heard of some people who've fitted the 4.5 inch F2 rim with 160 rear tire and (like you) have not had to trim the torque arm at all. But they tend to be outnumbered by those who had to trim the arm. I can only say that in my conversion, (5.5 inch rim, 180 tire) there's no way the stock arm, mounted in the stock location, would have worked.
Well I now have one problem. The pvm wheel is a modular wheel, and now the drive side has come loose. (I didn`t get it loose when I did the covensation for machining it, I had to get it to a shop that had a machin that fitt the whole wheel). Back to the thing, I belive it may have done some damage, not sure how much, havent taken the wheel off yet. If I have to find a new wheel, I cant proberly find a nother used pvm wheel, so I have lookd for dooing a 17" wheel svamp. I on the other hand was leaning for using a Kawasaki ZX6r rear wheel. why, its 5.0 wide and you can use 170/60 and 160/60 tires and has a 3 spoke disign that mach the pvm front I use. The ZX6 use a 525 chain, not a 530 but the vfr750R/RC30 uses a 525 chain and has the same splins on the drive shaft, so its front spocket can be used. As a bonus it pushes the chain line a bit outside for more clearens. Knowin that the oem calliper tuorge arm bends easyly is a good thing.
Sounds like the ZX6r rim would be a good choice - the 5.0 inch rim would also allow you to run a 160/70 tire if you like in order to regain some of the rear ride height you'll likely lose going to the 17 inch rim. The 525 conversion also sounds like a good idea, since it might help maintain proper chain alighnment with the new rim. Be sure to let us know what you end up deciding to do! fing02.gif
Pegasus, Sep 26 2006, 01:10 AM Going with the CBR1000F wheel was a decision I made based partly on precedence, and partly on opportunity. Originally, I'd been contemplating the YZF600 rear, but couldn't track down anyone who had done the swap. And, figuring I didn't have the skills (or patience) to be a pioneer, I was looking for a swap that had been done before. I had managed to find out about a couple of people who'd done the CBR1000F rear swap, and when one turned up cheap on Ebay in the right colour, with everything I'd need....well I took the risk and bought it. I also figured the CBR rim (being a Honda rim from the same era) might also offer additional advantages that would make the details of the swap easier, such as the same axle diameter, brake rotor bolt pattern, and sprocket bolt pattern (allowing me to re-use some VFR parts if needed). I speculate that a 4.5 or 5.0 inch rim would be a better fit for the VFR overall, both for the selection of tires that it offers and ease of fitment, but at the time I couldn't find anyone who'd fitted a 3 spoke wheel in that size.
Well, getting one for the right price sertanly change a thing, more so if the other option is hard to find. Funny thing, when I did my swap, and hunted for exampel, all I found was the f2 convensation and one GSX-R swamp by a "Steve". Well first I found the "Steve" VFR then looking for a swap option. He had a GSX-R 1100 usd fork and frontwheel, and a 5,5 GSX-R rear. The 750 GSX-R uses some year a 4,5 wheel thats otherwis identical to the 5,5 other than whit ofcorse. Someone did menthion that a cbr1000f wheel might fit, but no prof. Here some link to that awesome "Steves" GSX-R/VFR: http://hirovfr.ld.infoseek.co.jp/rc24/stvfr2.jpg http://hirovfr.ld.infoseek.co.jp/rc24/stvfr3.jpg http://hirovfr.ld.infoseek.co.jp/rc24/stvfr4.jpg http://hirovfr.ld.infoseek.co.jp/rc24/stvhiro2.jpg
Hope you like, It was these that inspired me to do the swap om my VFR.
By the way, the YZF 600, late 80, early 90 GSX-Rs and ->97 ZX6R use same axle diameter as the VFR.
I think it must vary from bike-to-bike. I have heard of some people who've fitted the 4.5 inch F2 rim with 160 rear tire and (like you) have not had to trim the torque arm at all. But they tend to be outnumbered by those who had to trim the arm. I can only say that in my conversion, (5.5 inch rim, 180 tire) there's no way the stock arm, mounted in the stock location, would have worked.
When I buoght my PVM rear wheel, it came whit a 170/60B18 Metzeler me1, man that is a huge tire (184 mm wide on that 5,0 rim). Whit that I would had to trim the torque arm for sure. Att that time I wanted to keep the standard chain line, and I did, but even I calculated it would just go inside the chain, it did just hit it whit that metzeler. ( I used the rear spocket to swingarm distanse as one mesure, and the spocket to wheel center to keep the mesurments stock, whell also spocket to rear brake disk to get all the same) I spot a 170/60B18 Continental in a local shop (someone ordered it but didnt pick it up) and it seems much slimmer than the metzeler. I got it cheap, and they ewen monted it up the rim for a test fit! It had no clearens problems. its 170 wide on the 5,0 rim. I have 3-4mm clearens o the torque arm, a bit more to the chain. The broblem whit the Conti have been it s proberly ment for a thinner rim, in 4,0-4,5 range and mounthed on that 5,0 rim it has a flat profile, giveing a slower steering aspesally now that its worn, and you go from edge to edge werry fast. Was planning to fit a 160/60 for next season. But now I noticed that glap in the wheel, dam I didnt noticed t sooner, just tough I had a litle too loos chain, whell I did have a loos chain, but not that loose... I whill keep posted when I have time to take off the wheel and see what damage it made.
One more thing about the ride hight after swamping a 17" wheel. I thing its easyest done by makeing new arms to the linkage, the steel one that are flat and betwen the alu linkage and frame. you can se thom in this pic, that also in a former post in this tread : http://www.vfrdiscussion.com/forum/uploads..._1241_12392.jpg
[image: IPB Image]
I know there is avable kits for some bikes using same thing to get a high rear, dont know their length, but it have to be shorter distanse betwen the mounting holes, a 4-5 mm shorter than stock I guess. These can easyty be made fron high qvality steel in same chape and just cut in right length and drill holes.
keny, Sep 26 2006, 07:42 AMI know there is avable kits for some bikes using same thing to get a high rear, dont know their length, but it have to be shorter distanse betwen the mounting holes, a 4-5 mm shorter than stock I guess. These can easyty be made fron high qvality steel in same chape and just cut in right length and drill holes.
I think you are referring to shortening the suspension linkage dogbones. I believe this would definitely be worth investigating, my only concern being that significant changes in the dogbone length might impact the shock linkage ratio enough that changes to the shocks spring rate and valving might be required for the best results. This isn't a big problem if you already have an aftermarket shock where you can change the spring or have it rebuilt, but might be an issue if you are trying to keep using the stock shock. The only way to find out if it works well would be to try it and see fing02.gif Differences between the '86 and '87 VFRs include changes to the shock linkage and shock length (10.63" in 86s, 11.0" in '87s). I had originally considered using my stock '87 shock with an '86 linkage (which bolts up to the '87 mounting points) to easily gain a lot of rear ride height. I decided against this when I found out that Honda changed the spring rates a considerable 25% between the two years to compensate for the slight changes in the linkages. With no inexpensive way to change the spring on my stock shock, I gave up on this idea and went with a longer shock instead. Another inexpensive alternative to another rear shock would be to have your existing shock extended (I know some folks, VeeferCanuck800 for one, choose this route when keeping their stock shocks with the 17 inch rear wheel conversion). If you do decide to do the dogbones, I'm very curious to see how it works out - be sure to post the details! beer.gif
Pegasus, Sep 26 2006, 01:10 AM Sounds like the ZX6r rim would be a good choice - the 5.0 inch rim would also allow you to run a 160/70 tire if you like in order to regain some of the rear ride height you'll likely lose going to the 17 inch rim. The 525 conversion also sounds like a good idea, since it might help maintain proper chain alighnment with the new rim. Be sure to let us know what you end up deciding to do! fing02.gif
No major damage on my PVM wheel, so no need to change... wheel.gif
Pegasus, Sep 27 2006, 11:15 PM I think you are referring to shortening the suspension linkage dogbones. I believe this would definitely be worth investigating, my only concern being that significant changes in the dogbone length might impact the shock linkage ratio enough that changes to the shocks spring rate and valving might be required for the best results. This isn't a big problem if you already have an aftermarket shock where you can change the spring or have it rebuilt, but might be an issue if you are trying to keep using the stock shock. The only way to find out if it works well would be to try it and see fing02.gif Differences between the '86 and '87 VFRs include changes to the shock linkage and shock length (10.63" in 86s, 11.0" in '87s). I had originally considered using my stock '87 shock with an '86 linkage (which bolts up to the '87 mounting points) to easily gain a lot of rear ride height. I decided against this when I found out that Honda changed the spring rates a considerable 25% between the two years to compensate for the slight changes in the linkages. With no inexpensive way to change the spring on my stock shock, I gave up on this idea and went with a longer shock instead. Another inexpensive alternative to another rear shock would be to have your existing shock extended (I know some folks, VeeferCanuck800 for one, choose this route when keeping their stock shocks with the 17 inch rear wheel conversion). If you do decide to do the dogbones, I'm very curious to see how it works out - be sure to post the details! beer.gif
Yes I menth the "dogbones". I do belive the lenght in them will not give big or any effect in the linkage rato. The linkage rato comes from the lenght betwen the svingarm mount, dogbone mount and shock mounth. The dogbones just holds the linkage to the frame. I know many that adjust the ride height of the bikes whit different length dogbones, mostly do to get the bike seat heigth lower. Suspension works as orginal after the change. (They do also lower the forks in the tripels to let steering stay normal. )
Finally! Got the 170 tire mounted on the rim, and back on to the bike for a test fit. There's now loads of clearance between the modded torque arm and the tire, and the chain no longer grazes the edge of the tire. Hmmmm....The chain guard is going to need some creative cutting to fit around the new tire, so I'll just leave it off for now.
Time for some (mostly) finished pics....
[image: IPB Image] Radial upgrade complete! Sportin' 170/60R17 Metzeler M3 on CBR1000F rim
[image: IPB Image] Side view 17 inch rims front and rear
....and a test ride! wheel.gif
First impressions?
"Dayum, I sure have missed my bike these last few weeks!" goofy.gif
Er, second impressions then?
Obviously, it's not as big of a transformation as the front end replacement. The first thing I noticed was how linearly it rolled into corners...very nice. I also noticed that steering effort seemed to be up a bit as compared to before. Hardly unexpected, but to be honest not as bad as I expected. Back to the garage to have a fiddle with the suspension. Considering that I was burning daylight, I decided to put my plan to drop the forks temporarily on hold to see what I could accomplish with a few twists. In an attempt to offset the slight drop in the rear, I went up considerably with the preload in the rear (not quite maxed out) and backed off the preload a notch in the front. Result? Still not ideal, but an improvement. I still plan to drop the forks some more, but even as it stands now, the bikes attitude is very close to stock.
So, what does it all mean?
"close to stock" wasn't really the effect I was going for with the radial conversion, so I can't wait to get my Fox shock sorted out! Now that I've got the wheel and tires done, it's time for an attitude (altitude?) change. I expect that another 1/2" drop in the front, and at least a 1" lift in the back will go a long way towards transforming the handling and making the bike feel a lot newer. Can't wait! biggrin.gif
"close to stock" wasn't really the effect I was going for with the radial conversion, so I can't wait to get my Fox shock sorted out! Now that I've got the wheel and tires done, it's time for an attitude (altitude?) change. I expect that another 1/2" drop in the front, and at least a 1" lift in the back will go a long way towards transforming the handling and making the bike feel a lot newer. Can't wait! biggrin.gif
Watch this space.....
Very nice, I bet the change will be more noticeable when you get into your favorite set of twisties and you find yourself scraping more and more hard parts due to the new, lower lean angle... idea3.gif beer.gif fing02.gif
Differences between the '86 and '87 VFRs include changes to the shock linkage and shock length (10.63" in 86s, 11.0" in '87s). I had originally considered using my stock '87 shock with an '86 linkage (which bolts up to the '87 mounting points) to easily gain a lot of rear ride height. I decided against this when I found out that Honda changed the spring rates a considerable 25% between the two years to compensate for the slight changes in the linkages.
I must have read uncearfully, but I first didn`t idea3.gif that differens betwen 86 and 87 shock and linkage. Well I remember that the works manula(hayns) says some differenses, but no actual mesurments. A strange thing is I got a Hagon shock on my, and Hagon lists the same shock for the 86 and 87! Bitubo has separate shocks for the 86 and 87. Well my old shock was toast, botoming two up rideing whit full spring preload easyly. Now whit the Hagon shock now sign of that, You dont have to adjust the spring preload at all betwen one or two up if you dont like, even I got the shock whit a hydralic one like the stock one, even so I use much preload to get the steering like stock. Ok I did do the shock swap and wheel swap the same time, but this got me thinking if I now has a 9mm shorter shock that there should be! ohmy.gif The suspension is stiff rear now, compared to the stock, that would explain the 25% spring stiffnes differens. Intresting comp13.gif
The stiffnes do mach the zx-r9 fork I have so no complain than I would like a faster steering.
