kcaut

I have an 83 Centurion Turbo on which I recently replaced the wheelset and tires. The bike did not have the original front wheel. The rear tire has very little clearance between it and the underside of the rear brake. If I am not careful when I position the rear wheel or if I inflate it to about 105 psi, the tire will run against the underside of the brake. The tires are Panaracer Pasela Tourguards (700 x 25c). I got the Shimano 105/Alex R400 rims from Velomine for Christmas. Would I gain much clearance if I changed to a 23c tire? Is it possible that different brands of tires might be a bit 'taller' when inflated and maybe I should get a different brand? I don't have any 23c tires to throw on there to see if if would make enough difference, if any.

Thanks for your help.

AZORCH

Here is the 700 x 23 clearance on the 1984 Turbo I used to own. Presuming that there's no difference between '83 and '84, it looks like a pretty good clearance to me. Hope this helps.

deuce8oh8

there is definitely a difference tire sizes across the board. different manufactures and different styles, added puncture resistance, added rubber, some have different shapes. some differences can make the difference of fitting the bike or not. i had a set of 700x28 nimbus armadillos that couldnt clear the fork crown but a 700x28 gator hardshell did. another thing is a wider rim will make for a lower profile tire and a narrower rim will do the opposite. if you have access to another wheel/tire then test fit it to see. i dont think a 700x23 of the same tire will make much difference in total height.

kcaut

I have different brakes and far less clearance. I do think my 25c tire looks taller than the one in your picture though. Am I wrong?

DiegoFrogs

I don't normally go as narrow as your tire, but I find the Paselas to be a bit taller than comparable tires of similar nominal widths, which usually measure very close to the nominal width on appropriately wide rims, unlike many of the other tires.

kcaut

Thanks for the responses everyone.

AZORCH, I just realized your picture had a 23C tire which may be why it looks somewhat smaller.I found this link, https://biketouringnews.com/component...al-vs-nominal/ which included some sample sizing on tire height/width from a single brand. Nothing for 23c/25c but for the 28c there was a variation from 24mm to 27.2m which certainly backs up what PMdeuce8oh8 said. Some time ago, Lascauxcaveman provided a page from the 1983 Centurion catalog. https://www.bikeforums.net/showthread...=#post15940297 which shows a 19.8 mm rim width but also shows it comes with a 25mm tire, so I think I should be able find a fit. This link https://velospec.com/components/alexrims/r400 shows the Alex R400 rims also have a 19.8 mm rim width so that hasn't changed with the new wheelset. I don't think I saved the tire that came off the back rim although I'm going to dig through the garage when its light tomorrow in case I still have it to see what size/brand it was.

eschlwc

a 25c tire should work on most all bikes accepting 700c rims. to be limited to a 23c tire seems wrong.

the pic you provided looks like the pads don't even reach the rim adequately. if this is the case, i'd replace the calipers. is the front clearance just as tight? post a pic of the front as well. cheers.

Campagnerdo 

The pad height is on a cam, and more pad adjustment looks like it is available, if needed (doesn't look bad to me). Those dia compe calipers are notoriously small, yet when the clearance problem is at the bolt, the size of the caliper is not necessarily the problem. If you replace the caliper, make sure the new one provides more clearance at the bolt itself, as a caliper that provides more tire clearance at the arms does not necessarily provide more clearance at the bolt. Pretty calipers, I vote for finding a shorter 25mm tire.

repechage

80's Turbos were built at a time where narrow tires were the rage... but this looks really tight for a 700c rim... It just LOOKS 27" to me...
But with those calipers and the rim/ pad match (And I don't like the match either as advised earlier)
I would for sure go with a more "sporting" for the era tire, 23c MAX. with less tread, not tour guard or heavy tread.
I too want to see what the front wheel looks like.
Pulling the rear wheel back in the dropouts will also increase the distance to the brake bridge. This I would do too, and adjust the brake blocks as low as possible, they don't have much adjustment to the eccentric, but there is some.

kcaut

There is quite a bit more room for the front wheel, which is image 1. The 2nd picture is the back wheel again with the brake caliper closed. It does look a little high to me, thanks for pointing it out. Campagnerdo is right about the cam and I have enough available to adjust it. I will also try moving the wheel back in the dropout. Good idea! thanks

The Golden Boy 

I have a 1978 Trek 730; 700 x 28 Paselas fit gloriously, but 32s hit the brake bridge. It's not an issue of the width of the tires, the height goes along with the width.

kcaut

Pulling the tire back as far as it would go looks like it will provide the needed clearance. I did let a bit of air out of the tire earlier today, so I'm going to re-inflate to what I normally ride at before we go out on tomorrows ride and see if it still has enough clearance but it certainly has more room then it did. Thanks all!

kcaut

Good point, I hadn't noticed that. Maybe there was a reason for that change in '84...