'97 Vfr Wheel On An '06+ Cbr Front End?

[chipdalejr]

I plan on doing a front end swap on a '97 750 for a newer CBR front end, but I want to keep the matching wheels.

Will the VFR wheel bolt directly onto the forks and brakes of the CBR or will I need to make spacers, not use the CBR brakes, or anything of the sort? I really want the better performance of the CBR forks, as I'm hoping to turn this bike into a relatively lightweight machine with all the suspension goodies to make it reasonably competitive with today's 600cc machines.

[CornerCarver]

You first need to clarify whether you are talking about a late model CBR600RR USD front or a CBR600F3 front.

Then you need to let us know what triple clamps you are using.

If the fork spacing of the new triples differs then you will most likely have to source spacers to match as well as correcting any resulting misalignment of the brake discs and brake calipers.

[slo1]

I really want the better performance of the CBR forks, as I'm hoping to turn this bike into a relatively lightweight machine with all the suspension goodies to make it reasonably competitive with today's 600cc machines.

It never will be, but it will always be a cool bike :)

[chipdalejr]

You first need to clarify whether you are talking about a late model CBR600RR USD front or a CBR600F3 front.

Then you need to let us know what triple clamps you are using.

If the fork spacing of the new triples differs then you will most likely have to source spacers to match as well as correcting any resulting misalignment of the brake discs and brake calipers.

I'll be using the USD forks, not the F3. I was told the triples would be a direct fit, but not entirely sure if that is true.

[chipdalejr]

I really want the better performance of the CBR forks, as I'm hoping to turn this bike into a relatively lightweight machine with all the suspension goodies to make it reasonably competitive with today's 600cc machines.

It never will be, but it will always be a cool bike :)

It will never be a supersport, sure, but I'd like to make the most out of what I can from it. I'll be doing a fork and shock swap, lightening it as much as possible, getting a custom exhaust, and more. I know it would make more sense just to buy a bike that is made for that, but the VFR is just so unique and cool. Plus, you can't get that sound anywhere else.

[CornerCarver]

You first need to clarify whether you are talking about a late model CBR600RR USD front or a CBR600F3 front.

Then you need to let us know what triple clamps you are using.

If the fork spacing of the new triples differs then you will most likely have to source spacers to match as well as correcting any resulting misalignment of the brake discs and brake calipers.

I'll be using the USD forks, not the F3. I was told the triples would be a direct fit, but not entirely sure if that is true.

I have not heard of anyone using the 600RR triples. That doesn't mean that they wont fit but I would think someone would have posted their use by now if they were a suitable candidate.

I am 98.7% sure that even if the RR triples will bolt into the VFR frame without any mods to the stem or stops that you will not have the same offset and therefore different handling characteristics (more trail from less offset will result in slower turn in at speed and an increased turning radius in parking lot maneuvers).

Most everyone else here has used some variation of RC51 and CBR929 triples to make the USD conversion.

[chipdalejr]

Would I be wrong in thinking that the RR triples, if they have different offset, which would be likely, would be more agressive? (Faster turn in)

[chipdalejr]

Found some more information off of another site. A 2009 RR front end bolts on directly, but there is a little tab that needs to be ground off. Don't recall what it was for, but served no use to the man I got the information from.

Did some digging and the different offsets for the bikes. The VFR is suposedly 40mm, and the RR is 30. How will this affect the handling of the bike? I thought less offset meant faster turn in and more responsive, but gave less straight line stability, yes?

If it helps, I'll be doing a shock swap at some point as well. I'm not as up to date on the info for the shock as I am the forks, but I think it lowers the rear a bit.

[CornerCarver]

Take a look at this thread as the responses that I received (along with pictures-I usually need pictures ) were able to help me better understand what is happening when you bring the forks closer to the centerline of the steering stem on our frames.

http://www.vfrdiscussion.com/forum/index.php/topic/64652-what-am-i-trying-to-correct/

[chipdalejr]

That helped a bit. Still confusing though.

[chipdalejr]

So, the the decreased offset is going to do what exactly with the handling of the bike? How would I correct the changed handling? Would I want to?

I know that I want the bike to be the type to be very responsive and quick in corners, as opposed to relaxed riding. Is that what I'll achieve by having the reduced offset or not?

[Rush2112]

So, the the decreased offset is going to do what exactly with the handling of the bike? How would I correct the changed handling? Would I want to?

I know that I want the bike to be the type to be very responsive and quick in corners, as opposed to relaxed riding. Is that what I'll achieve by having the reduced offset or not?

The reduced offest pulls the front axle back by ~10 mm, the steering angle remains the same so the trail will be increased by about 10mm making the bike more stable, not more responsive.

There is no simple way to correct the steering geometry without getting custom triples with the correct offset. Raising the rear will change the steering angle slightly and reduce trail getting you closer to where you want to be, but you change the geometry of the angle that the swingarm interacts with its pivot point altering the arc it travels through its full range of motion. Raising the fork tubes in the triples (lowers the front) also changes the steering angle and reduces trail but you lose ground clearance and have to consider interference with other parts when fully compressed.

Its all compromises... you have to decide what you are willing to accept

[chipdalejr]

Thank you for the response. It all makes sense now. I was taught that offset was different than it truly was. How bad will the 10mm change be? Is that too much to be able to have it corrected for the most part?

[Rush2112]

Thank you for the response. It all makes sense now. I was taught that offset was different than it truly was. How bad will the 10mm change be? Is that too much to be able to have it corrected for the most part?

I have a 5th gen, 2 of them actually, and I have details on those. The stock trail value is 95mm with 40mm of offset and 25.5 degrees of rake (steering angle); decreasing the offset to 30mm will increase the trail to about 105mm... an increase of about 10.5%. I don't know how much you would have to raise the rear and drop the front to compensate for all or part of that... I'm guessing a lot. I'd make some measurements and start a spreadsheet to find out

A rough calculation, keeping all other things equal, indicates you would need to decrease the rake/steering angle by about 2.68 degrees to get the trail back to 95mm.