jeffmendoza

I recently picked up an early-mid 70's Motobecane Mirage at the thrift store (I'll post pics soon). It has 27" straight-side rims. The tires were rotten, so I picked up some 28-630 27 x 1 1/8" tires. These are Vittoria brand rated for 100 psi (a quick google search finds them here).

So far I've had two blowouts, the first when I was initially pumping up the front tire to pressure, the tire slowly came off the rim on either side right around the valve. I attributed this to my complete lack of experience with road bikes. The hole in the tube looked circular, about 1-2mm in diameter.

I then got a new tube for the front, and pumped it up much slower, checking that the tire was centered every few pumps, and everything went ok.

The next blowout was on the rear while riding. I mounted the rear tire before the blowout on the front, so I'm not confident in that mounting either. One side of the tire came off the rim, and there was a 3-4" slice in the tube on the inside where it rests against the rim. It could be the cheap rubber band rim strip I used (I now have cloth), or the guy at the LBS said that I could have mounted the tire with some of the tube pinched between the tire and the rim.

Now, I'm looking over Sheldon's site, and I see this:

Anyone have any opinions? What are your personal experiences? Are my blowouts due to my inexpierence in mounting tires, or are my rims at fault? Should I run only 75 psi in these tires? I weigh about 140 pounds, will this be ok with 75psi in a 1 1/8?

dbakl

I have the old Weinmann clincher rims on my 72 Paramount and have suffered the tire blowing off. Its due to the incompatability of the older rim design and modern tires. Lower pressure and constant monitoring seems to help, but I'll replace my rims one of these days.

Some people have had good luck with specific brands of tires, but I don't know what those are...

arborohs

I run 27" tires with and without hook beads and like these and yes I run 90 psi with non hook beads. These tires are wider and I like the price.

https://aebike.com/page.cfm?PageID=30...ils&sku=TR5120

strawboss

I'm using Serfa Secas, 27 x 1.25 on my Schwinn World Voyageur with Araya straightwall rims. I weigh 200 and have them pumped up to 78-80 lbs. I have about 700 miles on these tires, with nary a blowout or a flat (knocking on wood). FWIW, I used to weigh 225 last summer, riding these tires at the same pressure. I've been pleased with them.

bikemore 

I am using Wienmann concave rims which I believe are straight sided (not
taking the tires off to verify it) and haven't had too much trouble (I had
a flat a few weeks ago, but I don't think that was because of the flat sides).
I have 1 1/4 inch tires and pump them to about 90psi. I've read elsewhere
in these forums that it is reasonable to ride then with moderately high pressure.
I weigh about 200 so running them at 75psi wouldn't be the best option for
me, but might work for you.

roccobike

+1, On straight side steel or alloy 27" rims, I use the same Kendas or a similiar tire marketed by Bell. Side by side, its almost impossible to tell the two tires apart. These are very similiar to the OEM Raleigh tires that came on my mid 70's Raleigh. I pump them up to 80 PSI and have no problems other than any road tire at 80 PSI can't compare to a hook bead, narrow tire at 100+PSI. But if you want to ride those rims, that's the sacrifice that has to be made. BTW, In my limited experience and ironically, cheap tires with a wire bead, NOT KEVLAR and not folding, work way better than more expensive folding/Kevlar tires because the wire adds rigidness to the sidewall.

Oldpeddaller

I've got several old road bikes with straight side 27 inch rims, both steel and alloy. I have fitted 27 X 1 1/4 Vee Rubber tyres and Michelin tubes to all of them, pumped to 80 psi with no problems. (These tyres are very cheap and wear well and I got the tubes as a job lot). I only tried to inflate to 100 psi once - the tube lifted part of the tyre bead away from the rim and I had to scrap both the tyre and tube. Not a problem, given the price - but on the road it may have been a different story! I really wouldn't risk 1 1/8 on these rims at higher pressures though.

!jayho!

I have an lower-end 80s Univega with straight side 630mm steel rims. Running a pair of Schwalbe Marathon tires, which I think are sweet. Had a friend do some work on the bike, and unbeknownst to me, he filled to max air pressure. I was riding down a slight hill (slowly, thankfully) in San Francisco, and had a rear tube blowout; sounded like a shotgun. Ever since then I keep them at about 80 psi and everything is great. No problems. I weigh 210 lbs. I ride on bumpy streets.

jeffmendoza

Thanks for the info. I rode around the block with 80 front and rear, and it just looks too low in the back, so I'll try 80 front and 90 rear. It was raining today, so I couldn't commute, we'll see how it goes tomorrow.

Caferacernoc

"BTW, In my limited experience and ironically, cheap tires with a wire bead, NOT KEVLAR and not folding, work way better than more expensive folding/Kevlar tires because the wire adds rigidness to the sidewall. "

Ditto. As you can see I have several bikes with 27" wheels. I think the old school tires, I use the $10 wire bead Kenda's, work the best and are way easier to deal with. I run 80 to 90psi no problem.

stronglight

I think one problem is that we have all (myself included) gotten used to thinking of modern 700c rims with narrower tires (23-25 mm.) as the norm for a bike. These are easily inflated to much higher pressures and naturally with modern hook bead rims this is not an issue. However, back in the 1970s before clincher rims began to acquire modern contours, clincher tires were most generally heavy recreational tires. Racing tires were exclusively the domain of sew-up tires and these could indeed handle pressures of 130 psi. These tires entirely enclosed the tubes, were literally glued onto their closed rims, and would never blow out. Them the development of hook bead rims created a subtle revolution. With the evolution into our familiar modern lightweight racing style tires, we are simply accustomed to a certain type of feel and handling on our wheelsets.

You might compare this difference to the spongy, high profile, highway cruising tires for an old Cadillac land-yacht, compared to the ultra-low profile high speed racing tires you will now find on a Porsche or Ferrari sports car where optimal handling is the goal. We like the handling of "fast" modern bike tires and the loose mushy feel of old style gumwall tires simply feels very wrong to us. So... we always increase the pressures of any of our road tires far beyond what would have been considered normal for tires a few decades ago, and far more than is ever really necessary just to prevent the tire/tube from "bottoming out" against a rim even if we do slam into a pothole.

With more rigid higher pressure tires mounted on modern rims, we loose the soft "suspension" feel - which the pneumatic tire was initially designed to give a bicycle. But, our modern clinchers certainly do corner very accurately and securely at very high speeds, and we will never feel our sidewalls swaying laterally on our wheels under these conditions. The Kenda tires are much like the classic clinchers of years past in both design and construction. They are softer, heavier, wider, have a higher profile, and they both handle and feel more like you're riding on marshmallows. This is not a bad thing (to my mind). Okay, to be honest, I'm really exaggerating the feel of these tires to stress the comparison to our thin tread 220 gram race-worthy narrow 700c tires, rated up to 130 psi. ... compared to the 450 gram, heavy steel bead Kendas which are perfectly happy loping along at 70-80 psi.

This is just one of the realities to consider when using earlier flat-wall style rims. I tend to consider what bikes I will mount my older rims on. And I am careful not to over-reach the limitations of those rims. For "nicer" (as in more modern style) better handling tires - even when I actually can find them available in 27" size - I will always opt for hooked bead rims. And the earlier 1960s Super Champion or Ambrosio rims I use on those bikes which I'll ride where lower pressures are more acceptable and are actually beneficial - like bike paths or park trails or even just very long yet leisurely road rides at slower speeds where the cushioning of the wider tires is most appreciated.

Just some thoughts to consider...

mrmw

+1

Beautifully said.

Kommisar89

+1 to Stronglight's comments, except...my 1974 Bottecchia came with Fiamme yellow label clincher 27x1 1/4 rims (edit: they are straight walled) with Clement clinchers rated at 100-psi and I loved them. And when they wore out I had a damned hell of a time replacing them with anything similar because all the 27x1 1/4 tires I could find or even 27x1 1/8 were like Stronglight describes. Bummer. I current run 700x28C on Rigida rims with the simi-hook or bump on them and they are just like Stringlight describes. I threw them on a scale and they weighed about 420 grams (almost a pound) more than my tubulars. No wonder I could feel the difference.

I have a 27" Super Champion (pre-Wolber) Gentleman rim I bought around 75-76 that is something like 13mm inside diameter with hooks so it would easily take a 27x 7/8 kevlar tire if such were available. I'd love to find a set like that in 700C.

rbman

Does anyone have any tips for mounting 27x1 1/4" tires on rims with straight sides? I have tried 2 different types of tires. (Specialized tri-sport, and Union Gumwall's) Same result, a "flat spot" where the tire won't distribute itself evenly along the rim. The tire "dishes" into the rim at a random spot. The rim is a Rigida Chrome Steel with rain dimples.(Vintage 1971) I'm sure this has something to do with the lack of a "hook" on the rim. The bike is a restoration and won't get alot of serious road time, but when I do ride it, it would be nice if the wheels felt round.

I've never had much of a problem mounting tires before this.

Thanks

wrk101

I use Kenda K35s on my hookless 27 rims and have not had the problem you describe. You need to make sure you use tires with a wire bead, or you will likely have a blow out. My non-wire bead tires made it one block....

My bike has araya alloy rims.

On my "blowout", the tire bead had completely come off the rim in one area, and the tube bulged out the gap. Wish I had a picture of it.

23skidoo

I've got several 27 x 1.25" wheelsets, including Wolber Super Gentlemans, Rigidas and Arayas and have used both the Vittoria Zaffirio 1 1/8 for a more economical but excellent tire and Panaracer Paselas in both the Tour Guard and Tour Guard Kevlar in 1" with great success.

I've not seen it mentioned here but have had three or four blowouts when mounting the tires due to pinch flats which happen when a small portion of the tube gets caught between the tire bead and the rim--it can be very exciting when you happen to be leaning over the wheel trying to get that last ten pounds of pressure into a 110 psi 1" tire and it goes kablooey right in your face. I've learned to totally deflate the tube and to carefully run a tire lever around both sides of the rim and it's easy to feel the difference between just tire bead/sidewall and that little bit of tube that got stuck in the wrong place and correct the problem before I inflate the tire.

When I really crave that wonderful ride from a 1.25" wheelset running at 90#, I've got a 31 year-old set of Araya alloy rims that still have the original IRC tires from my Trek TX300 and they're in much better shape than I am after all those years.

Rober

I have recently restored an early 80s Puch Austro-Daimler Pacifica with stock Belgian straight-sided rims. I used Vittoria Zaffario 1 1/4 tires (the ones the OP probably used also) inflated to 90#, as recommended. I have not ridden the bike a great deal (maybe 50 miles so far), but have not had any problems at all with blowouts or with the tires "jumping" the rim. I cleaned the inside of the rims very well and made sure there were no burrs or nicks, used new cloth rim strips, standard gauge Schrader valve tubes, and dusted the inside of the tires and the tubes liberally with talc before installing them. I checked to make sure the tire bead was seated well about three times while inflating the tires, and then ran them at 75# for a few blocks before inflating them to 90#. No problems so far.

rbman

Thanks,
I like the talc, and riding aound the block a few times with low pressure to "even things out", ideas.

Rode the old Falcon about 35 miles today. Other than the slightly odd roll to the tire, it went quite well. Not bad for a 37 year old bike. You sure do notice the weight difference between those old rims and tires (not to mention frame) and the modern stuff! However, once you get them rolling, you do have alot momentum!

CACycling

I've got 2 bikes with steel Araya non-hooked rims. I run the cheap Forte road tire in 27 x 1 1/8 at 100 - 105 psi on both. I blew a couple of tubes installing tires on the second set of rims (never had a problem with the first set although they look identical) but found that installing carefully and keeping them at or below 105 psi has eliminated any problems. I've put 1,000 miles on one of the bikes (my commuter) with no issues related to tire mounting.

Bikedued

I have a little trouble with the wire bead of some tires hanging up on the cloth rim strips. One time it was so bad it actually pulled the rim strip into the tire bead, showing a slight white edge. I had to work on it for nearly a half hour to get the bead seated, including using a little grease, but it eventually worked. I blew a Kenda off of a Mistral 27" just this evening during inflation, my ears are still ringing lol.(Mistrals look very much like mid 80's Arayas) It was dark, and I wasn't paying attention. I want to put some Pasela tour guard tires on that bike sometime in the near future. It was the first time I had ever used a Kenda 1 1/4" on a narrow rim, and it felt loose from the start, but did stay seated for several miles. I was fixing a flat when the tube forced it's way out.,,,,BD

Rober

I think there is more to this idea than most people realize. I can really tell the difference between my steel LeMond with alloy rims and 23mm tires and the Puch with steel rims and 1 1/4 tires. Once it gets rolling it is much easier to keep rolling.