700c Bead sizes - are they truly standard?

[trgz]

I previously ran Panaracer Pasela TG 700x28 for 18 years on MA40 rims (after previously running Panaracer Tourguards on my old 27" Holdsworth) and I probably only ever had two pinch punctures caused by hitting potholes/rocks. A year or two ago I decided to go over to something lighter - Conti Gatorskins 700x25 and boy were they hard to fit - I had to buy a VAR bead-jack tool to get them on and when I had a puncture yesterday I had to resort to a Stanley knife, 12 inch screwdriver and wire cutters to get them off the rim (after breaking the VAR tyre lever) - needless to say the tyre did not survive the process (having been cut right through). A spare, new, Pasela (I'd not used since buying it) went on without any tools as they always did - just my gnarly fingers were needed.
This frustration led me to ponder just how standard this ISO 700 (622mm) bead is and what problems I might have if I bought another puncture-resistant tyre like the Schwalbe's etc.
Any thoughts?

 

[Ajax Bay]

Take it you're sure that they are 700c and not 27"? MA40 rims have some notoriety for being difficult to mount/get tyres off and so do Gatorskins (others may be along soon to say that you just need robust thumbs and good technique).

 

[rrarider]

I can share my experiences with MA40s and two types of tyre. I had Specialized Touring 700x25 tyres fitted until the side walls perished when I replaced them with new old stock foldable Specialized Turbo S 700x25 models. Despite what some know-it-alls post, I have always needed tyre levers to get any tyres off my Mavics and with the new tyres I sometimes have used them to get the tyres on, when it's cold or my thumbs ache. Part of the reason is that the MA40s don't have a deep central well, in fact my Velox rim tape pretty well fills it. All that crap about 'pushing the bead right into the middle of the rim and you won't have any trouble without levers', just isn't true.

Some people maintain that Kevlar beaded tyres are easier to fit, some say the opposite - I just don't know. Maybe the trouble you have had has been down to a variation in manufacturing tolerances, again I don't know. I think I would risk buying another Gatorskin if I were in your position and spend some time practising in the comfort of your own home. Practice is always worthwhile, as by doing it, I found out that two sets of tyre levers were ony fit for the bin, when they snapped. I also discovered that the rubber solution in my bike's travelling kit had dried out.

 

[trgz]

Take it you're sure that they are 700c and not 27"? MA40 rims have some notoriety for being difficult to mount/get tyres off and so do Gatorskins (others may be along soon to say that you just need robust thumbs and good technique).

Definitely 700c on all counts (I do remember when I was a kid trying to put a 700c folding on a 27" rim - a definite non-starter!) - I have heard that the Gatorskins are problematic, and there's no channel to speak of in the MA40s, but 622mm is 622mm in my book so someone (Panaracer or Continental?) is doing something non-ISO in my book - I'm wondering if one measures the top of the bead as opposed to the bottom of it ?

 

[trgz]

I can share my experiences with MA40s and two types of tyre. I had Specialized Touring 700x25 tyres fitted until the side walls perished when I replaced them with new old stock foldable Specialized Turbo S 700x25 models. Despite what some know-it-alls post, I have always needed tyre levers to get any tyres off my Mavics and with the new tyres I sometimes have used them to get the tyres on, when it's cold or my thumbs ache. Part of the reason is that the MA40s don't have a deep central well, in fact my Velox rim tape pretty well fills it. All that crap about 'pushing the bead right into the middle of the rim and you won't have any trouble without levers', just isn't true.

Some people maintain that Kevlar beaded tyres are easier to fit, some say the opposite - I just don't know. Maybe the trouble you have had has been down to a variation in manufacturing tolerances, again I don't know. I think I would risk buying another Gatorskin if I were in your position and spend some time practising in the comfort of your own home. Practice is always worthwhile, as by doing it, I found out that two sets of tyre levers were ony fit for the bin, when they snapped. I also discovered that the rubber solution in my bike's travelling kit had dried out.

Done two Gatorskins (one front, one back) and both were nigh impossible to get on - in the comfort of my lounge (I even warmed them on a radiator first!) and struggled even with a VAR bead-jack tool. Just ordered some Paselas whilst I can (doing the LEJOG and there may be the odd gritted cyclepath and I can get them on without levers, though I need one to get them off). I think I'm going to veer away from Conti's for now and maybe try out a Schwalbe at some point, but I'd really like to find a source of actually bead measurements so I can be fore-armed/fore-warned.

 

[Spiderweb]

I have a big ride this weekend and needed to swap my CX tyres for new wired Gatorskins. They were quite difficult to get on but managed to gently lever them on with a decent plastic tyre lever.

 

[keithmac]

May be due to the construction of the bead and sidewalls as well.

Some motorcycle tyres are very easy to fit, but the same size tyre (different make) on an identical wheel can be a real nightmare due to its construction..

 

[Sharky]

The only tyres that came close to defeating me were Marathon +'s on Mavic Askium's,

Re levers - I have gone back to metal ones. Had too many plastic ones snap on me and they are quite thick to slide under the tyre to get leverage. I use ones like these now http://www.halfords.com/cycling/bik...vc:c|adp:1o2&gclid=CM_T7bzcyM8CFWsq0wodQ34MFw

 

[trgz]

I have a big ride this weekend and needed to swap my CX tyres for new wired Gatorskins. They were quite difficult to get on but managed to gently lever them on with a decent plastic tyre lever.

Fingers crossed you have a great ride - good luck getting them off if you puncture. My perfectly sound Gatorskin (that proved not to be that reasonably punture resistant) on the front is coming off, using wirecutters again no doubt(!) in the comfort of my home - can't afford the taxi home ;-)

 

[trgz]

The only tyres that came close to defeating me were Marathon +'s on Mavic Askium's,

Re levers - I have gone back to metal ones. Had too many plastic ones snap on me and they are quite thick to slide under the tyre to get leverage. I use ones like these now http://www.halfords.com/cycling/bik...vc:c|adp:1o2&gclid=CM_T7bzcyM8CFWsq0wodQ34MFw

Classic - takes me back to the days of using spoons as a kid :-)

 

[Yellow Saddle]

I think it is down to manufacturing tolerances. The ERTRO standards are standard. Just 1mm in circumference difference makes a huge difference in getting the tyre on or not. Also, the Kevlar beads stretch less than a steel bead of equivalent diameter and if not compensated for, makes the tyre a bitch to fit. Something else that contributes to difficulty in fitment is a soft juicy bead. An example is the bead of a UST tubeless tyre. These are thick and soft to make a good seal and they make the tyre lever difficult to slide around.
Then, some rims are just bastards. MA40 is one of them.

 

[trgz]

Then, some rims are just bastards. MA40 is one of them.

It does seem to be the consensus of opinion

As for the ERTRO (ISO 5775?), I think that is basically my issue ie "How standard really is this standard?". If I can remove one tyre almost without a lever (if feeling strong) yet have to resort to utter butchery on another tyre on the same rim to get it off then one, or both, is varying from the standard. I guess I'm correct in saying that 3.141mm difference in circumference equates to 1mm diff in diameter (Circumference = Pi x D) though how much play is actually needed for that last little bit to get over the rim must lie in a more complex bit of maths than that...

 

[Yellow Saddle]

It does seem to be the consensus of opinion

As for the ERTRO (ISO 5775?), I think that is basically my issue ie "How standard really is this standard?". If I can remove one tyre almost without a lever (if feeling strong) yet have to resort to utter butchery on another tyre on the same rim to get it off then one, or both, is varying from the standard. I guess I'm correct in saying that 3.141mm difference in circumference equates to 1mm diff in diameter (Circumference = Pi x D) though how much play is actually needed for that last little bit to get over the rim must lie in a more complex bit of maths than that...

You will be amazed at what a difference just a small change in diameter can make. I've proved this by reducing the wheel's diameter slightly by tightening the spokes and it makes a big difference in getting certain tyres on or not.

There's a certain brand of MTB tubeless tyre....name escapes me now (S-something, not Schwalbe), that's impossible to mount on a Stan's rim unless you tighten the spokes.

Edit: I've remembered what the brand of troublesome tyre is. GEAX. Therefore not S-something as I dreamt. GEAX is Latin for tighter than a duck's arse.

 

[Ajax Bay]

doing the LEJOG and there may be the odd gritted cyclepath

Is this a winter LEJOG? When are you starting?
I think you want to try Schwalbe Marathon Plus - in fact I have one that's done half a LEJOG (the second half). Once you've fitted one of those, any other tyre is a kitten.
Talc.

 

[andrew_s]

It's down to manufacturing tolerances.
I tried to replace a worn out Conti GP4S 28, which always had been an easy fit, and didn't need tyre levers to remove, with a new one, and failed completely, even using steel levers, a VAR bead jack, and lubrication (on Open Pro).
Eventually, I gave up, fitted a different tyre to the bike, and using a different rim with the thinnest available rim tape, got it fitted, and left it stretching at 160 psi (mostly) until the alternative tyre had worn out. By that time, it was merely a normal tight fit, deserving of keeping steel levers and the VAR in the saddle bag.