Bicycle Mechanics - Is it common practise to mount 27 X 1 1/8 tires on 27 X 1 1/4 rims?

Hi, I just picked up a Nishiki International road bike and want to replace the tires. It has 27 X 1 1/8 inch tires mounted on 27 X 1 1/4 inch rims. I was looking at a set of 27 X 1 1/8 inch Vittoria Zafirro at Nashbar. Is it cool to go with these? Also, If I do go with this tire/wheel size comination what wouls be the best tube size to use? Any and all information either pro or con would be appreciated! Thanks!! - Dan

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Cheers and welcome to Bike Forums, Dan.

I'm moving this to Bicycle Mechanics (from Introductions) where it might get more replies.

--Juha, a Forum Mod

Not a problem at all.
Get the 1 1/8 tubes, too.

Tubes fit both 700c and 27" tires and tubes cover a range of tire widths a so, get a tube labeled something like 700c x 28 - 32 and/or 27 x1 - 1/1/8". Tubes are pretty tolerant and a smaller tube (say 700 x23-25) will work in a wider tire.

27 x 1 1/8 tire on a 27 x 1 1/4 rim isn't unusual, but it isn't the best choice, either. 27 x 1 1/4 tires would be preferable, and are available. The narrower tire on the wider rim will require a higher pressure to avoid pinch flats & rim damage, and running a higher pressure has its own issues.

27 x 1 1/8 tire on a 27 x 1 1/4 rim isn't unusual, but it isn't the best choice, either. 27 x 1 1/4 tires would be preferable, and are available. The narrower tire on the wider rim will require a higher pressure to avoid pinch flats & rim damage, and running a higher pressure has its own issues.
My '85 Bridgestone 400 came factory stock with 27x1-1/8" tires mounted on Araya 27x1-1/4" rims so apparently the bicycle makers think it's an appropriate combination.

Generally it is OK to do so, but it depends on three factors - the actual inside width of the rim, the profile of the tire when mounted, and the conditions under which the bike is used. Rim widths for one labeled as 27 1 1/4 do not vary a lot but tires can vary quite a bit. If a slightly wider rim is paired with a tire that does not have a high profile then the rim can end up too close to the pavement. That brings in the third factor. If the rider is heavy, the bike is loaded, or the route is potholed there is a much higher likelihood of flats and rim damage. Be suspicious of tires that are significantly lighter than others of the same spec. the weight may have been saved by shaving down the size of the tire.

Absolutely safe to go with 27 1 1/8 tire on 27 1 1/4 rim. I use 27 1 1/4 tire on the Bridgestone 400 for a softer ride. Rolling friction between the two tires is negligible from the same model of tire.

It looks like the consensus answer is, "probably but it depends"... I used to have one tire 27x1 1/8 and one 27x1 1/4 and now have both 27x1 1/4 but wish I'd done both 27x1 1/8... At this point I'm too cheap to take off perfectly fine tires though.

Thanks for all the good information....and quick too! I think I'll go ahead and order those tires. Happy pedaling!!!

It looks like the consensus answer is, "probably but it depends"....
It really doesn't "depend". The bike makers used to do exactly that when 27" wheels were relatively common on decent quality bikes so there is no question it's a safe and effective combination.

Perhaps a 1-1/4" wide tire is the recommended width for that rim, but technically ANY 27" tire (with the same 630mm bead seat diameter [BSD]) will fit on it.

Sheldon Brown has a chart with recommended ranges of tire widths given the inside width of the rim. http://sheldonbrown.com/tire-sizing.html#width

It's all in millimeters, so convert from inches to millimeters with: inches x 25.4 = mm. 1-1/8" is about 28mm and 1-1/4" is about 32mm.

As you'll see in the chart, those two widths are so close to each other, they fall on the same range of rim widths, between 15 and 19mm.

27 x anything have the same bead diameter (630mm) that fits only "27 x anything" tires, not 700C
700C is the french dimension of a tire with bead diameter 622mm.

Conclusion:

27x 1 1/8 and 27 x 1 1/4 are fully interchangeable and are made to fit together.

700C, 622 tires will NOT fit a 27 x whatever rim.
http://www.sheldonbrown.com/tire-sizing.html

splukonik, i'm in a similar situation in which i accidentally ordered the smaller size.

i have a post somewhere, but the consensus is that because my rims are straight-sided with no hooked edge, i might have a problem.

are your rims also straight-sided so that you would be able to give me some qualified advice?

I've sold the bike that I put those tires on but I do believe the rims were straight sided and the 1 1/8" wide tires worked fine with no problems. Hope this helps!