Tire Experts - Rim Size vs Tire Size

M

mroberto

Well-known member
Hey all,

I've got a question for the tire-mounting experts. I have a front rim with a width of 2.5 inches. It currently has a 100/80/17 mounted. The rear rim is 3.0 inches wide with a 130/70-17 mounted.

I can't find tires that small around here but I can find 110/70 fronts and 140/70 rears.

Will those tire sizes fit upon the rims I have?
 
New model CBR125, by chance? Rim sizes sound right.

110/70-17 front and 140/70-17 rear will work.
 
You're close with Honda, but it's actually a 1987 CBR250R Hurricane. It's an MC17 grey-market bike from Japan.

in_garage.jpg
 
You'll have a hard time finding the 100 front...probably going to have to move up to a 110. If you want to stick with the 130 rear your only options are bias-ply. Michelin Pilot Activ, Pirelli Sport Demons, and BT-45's are the best rated and most common. If you want radials move up to the 140's.

Actually you can get Avon Road Riders in those stock tizes...
 
Can it be mounted on the rim....sure! I don't see how it would be a problem...if you are having issues - PM ME.

but the bigger issue...do you have enough clearance?! for chain, etc etc...
 
I know someone who has a FZR250 with the same rim diameters and widths. He used the BT003RS 110/70 and 140/70 tires, and liked them.
 
Thanks for all the help guys! The BT-003RS is the tire I was looking at. I'll have a look at the bike to make sure the slightly larger width will clear things like fenders and chains. As long as there's no issue there, the 110 and 140 are the ones I'll get.
 
I bought the Bridgestone BT-003RS in 110 front and 140 rear. I had Frekeyguy mount the tires for me (great service BTW!). After mounting the rear tire and inflating it to 40 PSI, he noticed that the tire was scalloped at both edges. The front tire seems to be OK, this scalloping is only affecting the rear tire. I've tried to take a photo to show what I'm talking about:

_MG_8310_zpsa72e9b9b.jpg


Do you guys know what's going on with this? Is it safe to ride on this tire? Is this going to cause me traction or suspension problems at full lean?
 
mroberto said:
this scalloping is only affecting the rear tire.
Click to expand...
Never seen it on a rear tire before. What's the recommended street pressure for that tire (not the max psi printed on the side)?

Great photo BTW :)

-Jamie M.
 
...also what is the date code printed on the sidewall.....maybe they are tires from an old stock?
 
Spin the wheel on its axle and check lateral runout. If it's OK and the tire balanced successfully without an excessive number of weights and a test drive reveals no issues, don't worry about it.

If it's just one spot like that, it probably has to do with the way a tire is manufactured - it starts out flat and then the ends are joined.
 
I'm not a tire expert but I wouldn't ride on that until I knew exactly what was going on with it.I'd atleast take it to a competent shop like pro6/z1 and hear what they have say about it before putting the wheel on the bike
 
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toysareforboys said:
Never seen it on a rear tire before. What's the recommended street pressure for that tire (not the max psi printed on the side)?
Click to expand...

The service manual that I have recommends 32 PSI for a 130/70-17 rear tire. I brought the pressure down to around 34 and didn't see any noticeable changes in the scalloping.


slowbird said:
...also what is the date code printed on the sidewall.....maybe they are tires from an old stock?
Click to expand...

The date code is 2911 so while it's older than I'd like, it's not terribly old. Certainly still serviceable, and still feels very soft.


Brian P said:
Spin the wheel on its axle and check lateral runout. If it's OK and the tire balanced successfully without an excessive number of weights and a test drive reveals no issues, don't worry about it.

If it's just one spot like that, it probably has to do with the way a tire is manufactured - it starts out flat and then the ends are joined.
Click to expand...

Frekeyguy balanced the tire for me and only had to put on one small weight. I tried to measure the lateral runout at the part of the tire where the tread meets the sidewall. With my somewhat inaccurate measurement setup, I measured +/- .012" of runout (the amount of lateral movement of the side of the tire in the same direction as the wheel's axis).

Feeling the tire last night, the scalloping doesn't seem too bad to me, but I'm certainly no expert and I want it to be ok. I also don't have the skill (yet!) to take the bike out for a test drive and get it leaned over far enough to ride on this area of the tire. Is it worth taking the tire to Pro6 or Z1 as was suggested? Frekeyguy also suggested that some heat cycles on the tire could help.

The scalloping isn't contained to one spot. It is around most of the tire, on both sides, but is worse in a few spots.
 
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Call/e-mail Bridgestone, they'll probably have the best answer. Show them that picture. I'm sure they'd replace the tire for free if they thought it was an issue, then just work out with freakguy for a deal on the swap.

-Jamie M.
 
toysareforboys said:
Call/e-mail Bridgestone, they'll probably have the best answer. Show them that picture. I'm sure they'd replace the tire for free if they thought it was an issue, then just work out with freakguy for a deal on the swap.

-Jamie M.
Click to expand...

I did that. Ended up getting in touch with the Engineering Manager at the Nashville office of Bridgeston Americas. He was extremely knowledgeable and helpful.

His take was that this issue is due to how the tire was banded for shipment. I'm not convinced because I believe the scallops are more frequent than the bands. He did say, however, that if it were caused by banding, then it's purely cosmetic and wouldn't be an issue.

He suggested that the larger, and more important, issue, is putting the large tire on a rim that doesn't fall within it's specification (rim is smaller by .75"). He didn't outright say, "Don't ride on this tire." He seemed to think that it would be ok if I didn't ride too aggressively. In a very worst-case situation, the tire would pop a bead, which he said was very unlikely. He thought it more likely that the tire wouldn't feel right or I wouldn't get the full performance benefits from the tire.
 
I had a tire that looked like that on my old stand up 33cc scooter... I was riding it one day and it literally exploded. 3" hole in the sidewall.

Sent from my SH-02E using Tapatalk 2
 
Op-take that tire off and put on a new one ,is the 100-150 worth your life ?

You've gotten a lot of iresponsible piss poor advice here imo ,if a new tire goes on a bike ,it should look proper and whoever installed that tire and let you walk away with it like that shouldn't be making a cent in the motorcycle industry
 
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