want new wheels = requires 4.5" --> 5.5"

[BK_856er]

I'm about to pull the trigger on some lightweight forged aluminum wheels for my M695.

Problem is, stock is a 4.5" rear rim width with 160/60 rear tire and 120/60 front tire.

All the aftermarket stuff is 5.5" rear rim width, which would pair with a 180/55 rear tire and 120/70 front tire (like the S2R).

So I shed some significant unsprung/rotating weight, but go up in rear tire width.  I have good aftermarket adjustable suspension all around, so I should be able to dial everything in.  My priority is handling/performance over looks and I already have a designated track bike, so this one is for ripping up the twisties.  Love to hear from anyone who has made the switch.  I'm worried that I might end up with something that rides funky.  I want the weight reduction, but I'm not sure about the 180 tire - how do those behave on the small monsters?

BK

(Here's the ride)

[Buckethead]

Basically, it's gonna feel like the bike weighs half as much as it does.

The profile of a 180 tire on a 5.5 rim is not that different from a 160 tire on a 4.5 rim. It's wider, yes, but it's basically the same "round-ness." The width is going to change the geometry of your front/rear contact patches *slightly*, but you're giving up so much rotational mass that you're going to notice how much easier it turns in more than you're going to notice that you require 1.5-2 degrees more lean angle to compensate for your new wider rear tire.

Also, nice ride. Love that color combo. 

[WetDuc]

Will the wider wheel bolt right on, no issues?

[Desmo Demon]

You can run a 170 on a 5.5" rim without any issues. My '98 ST2 with 5.5" rear rim came with a 170 from the factory. I generally run a 180 on it, though.

As for the 5.5" bolting on without any mods - I would assume it will. The extra inch in rim width should not pose any issues with clearance on the bike. A 170 rear tire would probably give you a better turn-in feel than a 180 (but less than a 160). The lighter wheels will make more of a difference than the 160/170/180 argument, though.

[Duck-Stew]

I'm doing this right now on a 695 swingarm in my shop.

Your existing caliper carrier and rotor will bolt-up w/o issues.  With regard to the chain side, here's the differences:

The existing sprocket carrier doesn't place the sprocket far enough away from the new tire to make it work.  You will need a 5.5" (25mm axle) sprocket carrier ***AND*** the sleeve which goes through the carrier bearings as well as the conical washer that sits against the swingarm.

Your existing chain guides on the bike will need to have the ridge removed so that the chain floats over them w/o issue (or you could find/buy the ST2 chain guides just be sure to get the ones from a steel swing-arm bike and I don't know what years those are).

You'll have to move the front sprocket to align with the rear (but that one's obvious if you're moving the rear sprocket....)



As far as tires go, I wouldn't run a 180 on the 695.  I'd go with a 170.  The further the mass is away from the axle centerline the greater affect it has on the inertia of the rotating mass.  So, what that boils down to is that that heavier the tire, the more you're already offsetting the benefit of the lighter wheels.  I'd run 170/60/17 in the rear and a 120/65/17 in the front.  That way, you're not shooting yourself in the foot with regard to rotational weight.


*(The 120/70 up front will, however, provide more cushion in the event you contact a pot-hole...  Just a suggestion on the 120/65...)

[BK_856er]

Thanks for the awesome info!

The 170 rear size seems like a good compromise here.  Unfortunatley my favored Pilot Power 2CT does not seem to come in that size, but others do, so I'll need to look into a candidate replacement.  That'll be a another big change.

I'll quiz my supplier on the fitment details.  I definitely want perfect alignment.  The wheels I have in mind require a comletely new carrier/sprocket in the BST design, so I thought that issue was sorted.  As for my upper rubbing block, well it's ridge is pretty much already worn down, so no problem there!

BK

[Duck-Stew]

For clarification on my end:

I'm putting aftermarket wheels that were designed for the M1000 onto an M695 using the stock M695 swingarm.  I don't think there's much you can do with the wheel design to move the sprocket further out to clear the wheel/tire without offsetting the wheel centerline too much....  But, I don't know first-hand so....

[Desmo Demon]

The existing sprocket carrier doesn't place the sprocket far enough away from the new tire to make it work.  You will need a 5.5" (25mm axle) sprocket carrier ***AND*** the sleeve which goes through the carrier bearings as well as the conical washer that sits against the swingarm.

Good point. My brain's a bit IZ_, but I think I do recall hearing that the carriers are different between the 4.5" and 5.5" rim models.

(or you could find/buy the ST2 chain guides just be sure to get the ones from a steel swing-arm bike and I don't know what years those are).

Steel swingarm are all '97(Euro)/'98 (USA) to '02 ST2 bikes and all '99-'0....'00 or '01 ST4 bikes (before the ST4s came out). The ST4s has the aluminum swingarm.....I don't know any of the details of the ST3 models, though.

[BK_856er]

These would seem to be the correct chain guides (from an '00 ST2 with steel swingarm):

44710301A     upper
44710311A     lower

The parts diagram shows the bolts on the opposite sides compared to mine, so that makes sense with respect to the offset.  Currently my chain nearly rubs my aftermarket rear hugger, which I guess is technically made for a 5.5" rim, so more offset in the outboard direction should put the chain in the middle of the opening/passage where this hugger expects it to be.

How do you handle the front sprocket?  Just flip it around and shim under the retainer as required to get correct front/rear alignment?  No case clearance issues with a 15t?

BK

[Duck-Stew]

Exactly.  Fornt sprocket gets flipped to provide proper offset.  Check chain alignment before assuming that is all you need to do.

[Monsterlover]

One thought that comes to mind (since you have a track bike)

Why change to a wider wheel at all on the rear?

What's wrong with a 160 tire?

If you're spending money on trick wheels to get that weight reduction, why back slide by going to a bigger wheel and tire (and adding weight)

Plenty of heat can be brought by a rider with a 160 rear. . .

[Duck-Stew]

One answer is that aftermarket wheels for Ducatis are only found w/a 5.5" rear width or wider (5.75" or 6").  The aftermarket hasn't done 4.5" wheels to my knowledge (please someone prove me wrong...).

[Monsterlover]

Oh.

Well then. . .

[BK_856er]

One answer is that aftermarket wheels for Ducatis are only found w/a 5.5" rear width or wider (5.75" or 6").  The aftermarket hasn't done 4.5" wheels to my knowledge (please someone prove me wrong...).

Exactly.  I have no issue with a 160 on the M695, but I don't want to put one on a 5.5" rim.  I just want to add lightness.

BK

[Monsterlover]

Hmmm. . .

add lightness. . .

is that like military intelligence?



Point taken though.