Rim and Tire Incompatibilities?

Quoted post said:

Originally posted by dennis dee
It may sound like a lot of BS but I recently read about this strange rim/tire incompatibilities. It's a case of French tires fitting into French wheels and Italian tires fitting into Italian rims but not vice versa. Apparently an Italian brand such as Vittoria Rubino will hardly fit into a French rim such as a Mavic MA3 (for example). But a Michelin will have no problem fitting the Mavic MA3. On the otherhand the same Vittoria will fit an Italian rim such as an Ambrosio. Does this sound plausible? I wonder if anyone experienced the same.

Some tires and rims are either undersized or oversized.
I never thought of it as a nationality issue before.
My experince of fit difficulties were related to Specialized tires fitting on Campagnolo rims. The Specialized tires needed a lot of coaxing to get on the rim... one of the few times I have needed tire irons to get the job done.
I haven't used Italian or French tires for quite some time, but I build wheels with a lot of French and some Italian rims.

Quoted post said:

Originally posted by daveornee
Some tires and rims are either undersized or oversized.
I never thought of it as a nationality issue before.
My experince of fit difficulties were related to Specialized tires fitting on Campagnolo rims. The Specialized tires needed a lot of coaxing to get on the rim... one of the few times I have needed tire irons to get the job done.
I haven't used Italian or French tires for quite some time, but I build wheels with a lot of French and some Italian rims.

You're definitely right about Campagnolo rims. I think they're a little bit oversize and have heard the same complaints from consumers and mechanics alike.

Agreed. I wouldn't limit the incompatibilities to just French and Italian. All mfgs have assigned plus/minus tolerances to guarantee interchangeability. It could be harder or easier depending on where your tire/rim combo falls in this plus/minus range.

A clincher should never be too easy to install. If it goes on with not much effort using your hands, I would be concerned with a possible blow-off.

Quoted post said:

Originally posted by dennis dee
You're definitely right about Campagnolo rims. I think they're a little bit oversize and have heard the same complaints from consumers and mechanics alike.

well,maybe it's the spoke bed depth and not necesarily the 'size' as determined by bead seat diameter??

HED has a warning on their site now that some clinchers are not recommended for their wheels. Affected wheel/tire combos have apparently been known to blow off the rim on extended braking due to heat. Ouch. Check it out:

http://www.hedcycling.com/

Quoted post said:

Originally posted by graf zeppelin
HED has a warning on their site now that some clinchers are not recommended for their wheels. Affected wheel/tire combos have apparently been known to blow off the rim on extended braking due to heat. Ouch. Check it out:

http://www.hedcycling.com/

You won't have that problem with Specialized clinchers. Ever since the early '80s they've had a reputation as being one of the hardest to mount. I've used them on three different bikes/rims and they are an absolute [censored].

Quoted post said:

Originally posted by p55mac
You won't have that problem with Specialized clinchers. Ever since the early '80s they've had a reputation as being one of the hardest to mount. I've used them on three different bikes/rims and they are an absolute [censored].

I kind of agree with "Boudreaux". It seems nowadays that it has a bit more to do with the spoke bed depth. At least as printed on most rims and tires the "size" is set at 622mm...not that that means much really. I have noticed that the new Shimano wheels are quite a bear when changing almost any tire. And also the same with Trek's house brand rims. But a difference of 1mm in size can mean a lot. I guess also it seems more like differences in the rims than the tires...

Quoted post said:

Originally posted by Philman
I kind of agree with "Boudreaux". It seems nowadays that it has a bit more to do with the spoke bed depth. At least as printed on most rims and tires the "size" is set at 622mm...not that that means much really. I have noticed that the new Shimano wheels are quite a bear when changing almost any tire. And also the same with Trek's house brand rims. But a difference of 1mm in size can mean a lot. I guess also it seems more like differences in the rims than the tires...

Well, the variation is occuring on the outside diameter. I don't think it has anything to do with spoke bed depth (rim depth). True, today's rim depths are deeper than ever, but that effects the inside diameter. If you look at a rim cross-section, that 622 bead seat diameter and bead hook is always placed on the outside. IMO, the discrepancy probably occurs after the extrusion process, when it's sized and cut for a specific rim, and rolled into a hoop.

Quoted post said:

Originally posted by p55mac
Well, the variation is occuring on the outside diameter. I don't think it has anything to do with spoke bed depth (rim depth). True, today's rim depths are deeper than ever, but that effects the inside diameter. If you look at a rim cross-section, that 622 bead seat diameter and bead hook is always placed on the outside. IMO, the discrepancy probably occurs after the extrusion process, when it's sized and cut for a specific rim, and rolled into a hoop.

Came across some interesting technical rim & tire info by German tire maker Schwalbe. The article discusses ERTO's rim & tire standards, fitting issues, mfg tolerances, etc. I stand corrected.......I thought the 622 bead seat diameter was close to the bead hook or rim flange, but that is not the case. It appears BSD is at or close to spoke bed depth, or the intermediate wall. Check out the two links below. The PDF link is the easiest to navigate.

http://www.schwalbe.co.uk/pdf/techinfo.pdf
http://www.schwalbe.com/index.pl?punkt=260

Quoted post said:

Originally posted by p55mac
Well, the variation is occuring on the outside diameter.

Where do you get that?

Quoted post said:

Originally posted by boudreaux
Where do you get that?

.....from my bruised knuckles. 🙁

Quoted post said:

Originally posted by p55mac
.....from my bruised knuckles. 🙁

You are not thinking it thru either. I ain't drawing a picture .

Quoted post said:

Originally posted by boudreaux
You are not thinking it thru either. I ain't drawing a picture .

Help me understand, boudreaux........show me an engineering drawing. Hell, even the 1'st article, calipers & gages would be nice.

I've had no trouble (well all 700c tyres seem to be a bit of a pain, but no bruised knuckles or any serious trouble) with Vittoria tyres -- Tecno Sport TT ([censored] tyre BTW, don't buy these), Rubino Pro and Open Corsa CX (both excellent) and Mavic rims; CXP21 and Open Pro.

The only rims I've really heard tyre installation horror stories about are Campy rims. Shame really, it's the only reason stopping me from running one of their wheelsets.

Related question -- has anyone got any experience re: tyre mounting issues (or anything else, for that matter) with DT Swiss' new RR1.1 road rims?

p55mac, i think what boudreaux is trying to say is that the deeper a rim is from the outer diameter to where the spokes bed has a lot to do with tyre mounting. If u think about this it makes a lot of sense (i personally agree with boudreaux and Philman). If a rim has a very deep spoke bed depth then the tyre can be mounted further around the rim before it becomes excessively tight. Think about this........
Q) where is the hardest part of mounting a tyre?
A) the last part when trying to pull the tyre over the rim once it is tight all the way around.

Q) What part of the rim is the tyre pulling tight against when this last part of mounting is being done?
A) the inside diameter (ie the spoke bed) on the opposite side of the rim to that which you are trying to pull the tyre over.

Q) where could some gains be made in regards to mounting a tyre with minimal stretch that is the correct size for a given rim?
A) the spoke bed depth could be increased, or the outer rim diameter could be decreased (although this would contradict the correct size part of the question and create an unsafe rim)

i hope i havent confused anybody any more, and i certainly hope that i have cleared up some confusion. Im not saying that there isnt a difference in rim size between manufacturers, although in my opinion it is most likely the spoke bed depth that effects tyre mounting the most.

Quoted post said:

Originally posted by drewjc
p55mac, i think what boudreaux is trying to say is that the deeper a rim is from the outer diameter to where the spokes bed has a lot to do with tyre mounting. If u think about this it makes a lot of sense (i personally agree with boudreaux and Philman). If a rim has a very deep spoke bed depth then the tyre can be mounted further around the rim before it becomes excessively tight. Think about this........
Q) where is the hardest part of mounting a tyre?
A) the last part when trying to pull the tyre over the rim once it is tight all the way around.

Q) What part of the rim is the tyre pulling tight against when this last part of mounting is being done?
A) the inside diameter (ie the spoke bed) on the opposite side of the rim to that which you are trying to pull the tyre over.

Q) where could some gains be made in regards to mounting a tyre with minimal stretch that is the correct size for a given rim?
A) the spoke bed depth could be increased, or the outer rim diameter could be decreased (although this would contradict the correct size part of the question and create an unsafe rim)

i hope i havent confused anybody any more, and i certainly hope that i have cleared up some confusion. Im not saying that there isnt a difference in rim size between manufacturers, although in my opinion it is most likely the spoke bed depth that effects tyre mounting the most.

Damm! No hooey points for you. 🙂

Quoted post said:

Originally posted by drewjc
p55mac, i think what boudreaux is trying to say is that the deeper a rim is from the outer diameter to where the spokes bed has a lot to do with tyre mounting. If u think about this it makes a lot of sense (i personally agree with boudreaux and Philman). If a rim has a very deep spoke bed depth then the tyre can be mounted further around the rim before it becomes excessively tight. Think about this........
Q) where is the hardest part of mounting a tyre?
A) the last part when trying to pull the tyre over the rim once it is tight all the way around.

Q) What part of the rim is the tyre pulling tight against when this last part of mounting is being done?
A) the inside diameter (ie the spoke bed) on the opposite side of the rim to that which you are trying to pull the tyre over.

Q) where could some gains be made in regards to mounting a tyre with minimal stretch that is the correct size for a given rim?
A) the spoke bed depth could be increased, or the outer rim diameter could be decreased (although this would contradict the correct size part of the question and create an unsafe rim)

i hope i havent confused anybody any more, and i certainly hope that i have cleared up some confusion. Im not saying that there isnt a difference in rim size between manufacturers, although in my opinion it is most likely the spoke bed depth that effects tyre mounting the most.

No confusion at all, drewjc. Thanks for the "picture" (it reached my frontal lobe). For safety/liability reasons, it will probably never change. At least to a certain extent, we have run-flat tires. Any deeper and the tire may come off as easily as it went on.

Quoted post said:

Originally posted by p55mac
........For safety/liability reasons, it will probably never change. At least to a certain extent, we have run-flat tires. Any deeper and the tire may come off as easily as it went on.

There's actually an effort underway by some at MIT to have better, more consistent standards in order to improve run-flat performance of bike tires & rims. How far will it go.......who knows. Cycling’s growing popularity will inevitably bring more liability lawsuits, forcing the industry to make revisions. If implemented, tire fitting may become even more difficult.

FWIW, no problems at all mounting Vittoria (Open CX and Rubinho) on Mavics. Not that much trouble getting them on Campagnolo rims either.

But maybe it's just me.