gregstandt

I've been rebuilding an old road bike and wasn't real sure of the rim size. (I got them on a trade with no tires on them). Anyway I bought some 700c tires and mounted them and they went on hard! I mentioned this to a friend and he said they might be 27" rims. Is it possible if you're dumb enough and strong enough to make this mistake?
The rims are a good quality aluminum and I thought 27'' were the old chrome rims.
Thanks, Greg

demoncyclist

Highly unlikely that you would get them on if that were the case. Some tire/rim combos are just really snug. They will probably loosen up a little with the miles.

operator

There are 27" AL wheels out there. Still made, easily available as well. And yes it IS possible to fit a 700c tyre onto a 27" rim. Good luck getting it off though. On the upside you won't be fixing any flats out on the road.

Al1943

Michelin Pro Race 700c x 23mm tires fit very tightly on my RR 1.1 rims. I don't believe they would fit on any 27" rims. How tightly tires fit rims varies a lot from brand to brand. I've never seen a 700mm that would fit a 27".

Al

operator

I have.

AEO

I can't remember, but I think it was either continental or schwalbe made a tire that fit both 622 and 630mm rims...

operator

Rofl.

Seriously?

AEO

yeah, I wish I could find that post...

might have been 635 and 630 mixed tire... oh well.

illwafer

i bet you could mount a schwalbe 700c on a 27" rim.

AnthonyG

I don't believe that you could mount a 700c tire on a 27" rim. 700c has a bead seat diameter of 622mm and 27" has a bead seat diameter of 630mm. Thats an 8mm difference and its simply not going to work. If the difference was under 4mm it might just work but not 8mm.

Anthony

531Aussie

^ I agree: I also would think it's impossible. Even some 700 tyres are almost impossible to fit on 700 rims, so I can't see it happening.

Anyway, if you want a looser tyre for easier fitting, I've found that some Scwalbe and Maxxis tyres are very loose. In fact, I had a few Maxxis Columbierres which were so loose they blew off my Velocity Deep V.

cyclodan

operator wrote: "I have"

Pic's please

tatfiend 

I have an NOS pair of 700c Michelin HiLite Touring tires I just installed and they went on incredibly easy. So far staying on the Velocity Dyad rims but I am keeping my fingers crossed.

operator

Don't have pictures.

This was a flat fix on a customers bike. There's no reason for me to lie. Other experienced mechanics may have seen this before as well.

Sixty Fiver

635 is an English 28 (over sized) and it is conceivable that someone might be able to get a 630 mm (27 inch tyre to fit but you'd probably have to cut the bead to get if off.

I have never seen 700c tyre mounted to a 27 inch rim.

Not saying that it can't be done and would bet getting the tyre off and on was as brutal a job as there could be.

griftereck

I used to work at Halfords
they sell an Apolo CX10 thats a hybrid with 700c rims
but the stock tyres are such a bad fit I reckon they would fit on 27" rims.
I should have tried one on my 1978 Dawes Galaxy, when I had it there.
Ive got a CX10 rear wheel on my Torino. A customer gave it to me as he was getting a new wheel under warranty. Was breaking spokes. I threaded up some spokes and its ok now. It works ok with the 700c tyre Ive got on it.

jccaclimber

Also no pics, but I've seen it as well. Thinking about it, it isn't a new tire by any means but, I'll bet I could get my really old used Vittorias on a 27 inch. They are tight on 700c when they are new, but after several years sitting mounted and aired up, but not being used all that often, they are so loose I have to help them stay lined up on inflation if I replace a flat. Those around 4-8 years ago may remember Vittoria clinchers having the beads "stretch" a bit through use. I remember a couple wheel manufacturers having warnings on their web pages about the use of Vittoria tires.

operator

Didn't bother getting it off. Just cut it off. Shop time was too valuable to have one guy struggle for an hour to get it off.

Sixty Fiver

I had someone mount a 650 B tyre on a 650 A rim once... it had to be cut off.

There's a 6mm difference in rim sizes there.

TallRider

27" rims made of aluminum aren't uncommon. I have four bikes with 27" aluminum-rimmed wheels, some of which I built up myself, most of which are original.
But it's true that the 27" standard tended to be used on lower-quality bikes and are thus commonly found with chromed steel rims as well.

tatfiend 

A friend's 1985 Raleigh Technium 400 has aluminum 27" rims. The bike is totally stock so far as I know.

silver_ghost

Operator's right. I don't have pictures, and no, I can't prove it, but when I was young and silly I wrestled a 700x30 Marathon onto an unlabed, 27" rim. The bead didn't seat (obviously) but it was still mounted on the rim. My boss was able to get it off (it didn't even take that long, just a few minutes of sweating and swearing) and I was given $#!t accordingly.

ogbigbird

(wow guys) id never seen a 700c tire fit a 27" rim, and even if a few types could, don't mean they should. if your rims are 27's, then find a nice set of 27" tires to install. i know selection isn't the best, but surely you'll be able to find something out there. then either sell, return or trade off the 700c tires. ...or get 700c rims, put the tires on normally (with the expectation you will have no probs getting them back off or back on) and use the 27's as back up.

silver_ghost

OP, if you did manage to mount the wrong size tire, it will be very obvious when you spin the wheel in your hands. The tire will be far from round and will bob all over the place. Hopefully that isn't the case. Good luck!

gregstandt

Thanks for all your input.

The tires seem to be seated well and the little ridge above the bead is visible. I think it's just one of those hard tire/rim combos. I'll know more when I get a flat.