MrVo

I have a pair of 27x1-1/8 tires. Then I bought the Sunlite Bicycle Tube 700 x 28-35 (27 x 1-1/8 - 1-1/4). But after taking them out, they look larger than my 27x1-1/8 tires. I'm not sure after inflating them, will they fit or not. I crumble the slacks and just tug the tube inside the tire. Any problems you foresee?

Bill Kapaun

IF they' fit a 700x28mm, they should certainly fit a 27x1-1/8 (28mm).
The tube will be stretched SLIGHTLY to fit the 8mm larger dia. 27" rim.

TallRider

tubes for 27" (630mm) and 700c (622mm) are totally interchangeable, so long as you have the proper valve stem. (27" rims are more likely to have schraeder valves, while 700c rims are more likely to have presta. but that's just probabilities.) there is plenty of flex in rubber.

fietsbob

for all intents and purposes, 28mm =1 1/8, 32mm = 1 1/4".

MrVo

The old inner tubes have the Schrader valve stem. These new tubes that I bought have the Presta valve stems. Can I still use them?

seeker333

Maybe. You can buy a Presta to Schrader adapter, pair costs <5 bux. You can use the Presta without the adapter, but there's a chance the tire pressure will cause the rubber to abrade/cut on the sharp edge of the the larger diameter Schrader valve hole, resulting in a flat. Additionally it would be a flat that can't be repaired with normal patch due to the proximity to the valve and hole. The better solution is to exchange tubes for ones with Schrader valve.

MrVo

Thanks.

sreten

Hi,

Schwalbe and Conti sell Presta tubes with a stepped retaining nut that fits Schrader holes.

Most Presta to Schrader adapters are for using a Presta valve with a Schrader
pump and wont remotely address the issue of the valve and the hole fit.

Your need to search for Presta to Schrader rim adaptors.
Bike shops probably sell the Mavic plastic grommet inserts.

rgds, sreten.

RubeRad

This reminds me, I once included a presta-to-schraeder adapter on a Nashbar order, the thing that I got had no rubber seal inside, didn't work at all. Buy one in a local store, they will often have screw-top jars full of them on the sales counter, should cost you only a dollar or two.

Also about tubes, I find they are pretty forgiving. For instance, I don't mind putting a 700x23 tube in a 700x37 tire. They stretch, that's the point of them.

However, there's this kid I know, just getting into biking, he kept having terrible explosive flats, turned out he was putting 24" tires into 700C wheels. That's just taking it too far. But 700 to 27" seems quite reasonable (as others have already indicated)

RubeRad

Just read again; if you have Schraeder (big) holes in your rim, your best bet is to use Schraeder valve tubes. You can maybe get by for a while by taking an old tube, cutting a 1-inch square out of it, slice a small X in the middle, and poke the presta valve through; use the piece of old tube as a protective "washer" for the larger hole.

But it will probably eventually fail, and you will need to buy schraeder replacements anyways. So you could try to get by for as long as possible with what you got before replacing, but tubes are pretty cheap, I would use the right tubes in the first place (and I'm a pretty big cheapskate, I take cheap shortcuts whenever I can, but I wouldn't here).

Darth Lefty 

Schwalbe website with size chart. Note some tubes have wider range and ranges overlap. You're almost certainly ok. These tubes come with the adapter nut.

https://www.schwalbetires.com/bike_ti...ta_valve-40_mm

MrVo

Results are in... And they fit!!! I went to my LBS and bought 2 Presta nuts and a Presta to Schrader adapter so that I can inflate the tires. I screwed the Presta nuts all the way down to the end of the valve stem, then plug the stem with the nut through the hole of the rim, then screw the another Presta nut ontop of the stem to secure the valve. I inflated the tires to 80psi, didn't want to max out to 90psi.

Kimmo

This is a pretty minuscule risk, thanks to the reinforced area around the valve and the fact the schrader hole is only about 2mm larger.

10 Wheels

You did good.

Wanderer

You can also get a rubber grommet, that goes into the hole in the rim, filling any excess space, and the presta valve fits perfectly inside that.

cny-bikeman

What you did is not advisable and may cause problems down the road. Using both the adapter and the extra nut will raise the stem base away from the rim significantly, causing the tube to have to stretch further when inflated in order to reach the rim surface. That could cause a stress hole and flat by the valve stem. You need to remove the nut you added inside the rim. Secondly, as noted in the chart supplied by Kimmo, 80psi may not be enough depending on your weight - or may be more than you need. Finally, when using presta nuts on the outside of the rim it's important to keep tire pressure maintained. Otherwise the tire/tube may migrate and you will not know it, as the valve will remain straight rather than tilting, which is normally the case.

RubeRad

Yes, that chart linked to by Kimmo is the best quantitative inflation guide out there. Just be aware the weight axis is per wheel; so you take the total weight of you, bike, and load, and either measure with a scale, or it's good enough to guesstimate, the distribution, they suggest 45/55, but when I took the trouble to get on my bike with either wheel on a scale, I measured 85.6/157.8 (that's 35/65), and that's unloaded. Adding my typical commuting rack&bags added only a few pounds, and didn't make that much of a difference.

MrVo

I read it somewhere on other forums that was the advice they gave to avoid pinching to the tube. I guess I can cut a rubber piece from a pen and tug the valve stem through it and use that as a grommet. I'll try it again later tonight.

cny-bikeman

No idea what you mean by "rubber piece from a pen," but you already have a grommet (presta/schraeder adapter) that has been used for decades by itself with no problems. Keep that but remove the extra inside nut. One avoids pinching the tube with proper installation techniques, not by adding more junk inside the tire.

You have to be very careful about whose advice you follow. Anyone can say "it worked for me." Personally I have not found another forum with as many well-qualified contributors as this one. The advice on the Bicycle Tutor forums is sometimes sketchy, and the moderators are downright hostile to suggestions of taking the bike to a shop.