are small-wheeled tyres always a tight fit?

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slowster
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Re: are small-wheeled tyres always a tight fit?

Postby slowster » 9 Aug 2018, 7:11pm

Brucey wrote:You are right, those tools (being meant for bullying an inflated tyre onto the rim shoulders when it doesn't really want to go) are complete overkill for the task in hand, capable of exerting about x20 more force than is required.

Unior market their tool specifically on its ability to remove difficult tyres (rather than seating an inflated tyre), e.g. as demonstrated in the video to which I linked.

JJF
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Re: are small-wheeled tyres always a tight fit?

Postby JJF » 9 Aug 2018, 8:02pm

I too am mystified by the problem of fitting tyres on 20" wheels. I didn't used to be.
For a few years my partner and I have used Schwalbe Marathon Plus tyres (20x1.35 or 35 406). I found them easy to remove with 2 tyre levers and replace using fingers only. Easy to cope with out on the road.

For a short time I tried Schwalbe Big Apple. They were difficult to fit and remove. I stopped using them because I didn't like their riding characteristics.
So I bought new Schwalbe Marathons as described above. I'm amazed at how difficult they are to fit. I had to resort to tyre levers and one of those devices mentioned in other posts.
It appears to me that the manufacturer has changed the characteristics of the tyres. I wonder if the beads will become more workable with use? I will watch this thread with interest to see if there is a favourite brand.

Brucey
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Re: are small-wheeled tyres always a tight fit?

Postby Brucey » 9 Aug 2018, 8:12pm

Slowster, fair point about the video but when those tools were first developed (they have been around for decades) there was no such need, (basically because tubeless bicycle tyres/lipped bead seats didn't yet exist).

And in this case the force the tool can develop is still ~x20 what is required; it is not that the tyres are especially hard to push off the bead seat, it is that my chum isn't very strong. A ~10kg squeeze would be plenty with pretty much any 'normal' tyre and rim, but they can't manage that; 2-3kg might be OK though.

Part of the trouble is that one hand is on a tyre lever of some kind, maintaining pressure so that, as slack is generated, part of the bead is lifted and thus where the bead is down in the well, it stays there. This leaves only one hand to push the bead off the seat; also a momentary loss of pressure on the tyre lever often sees the tyre bead pop right back up/on again. This last thing is (I think) most likely to happen with smaller wheel sizes.

cheers
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Brucey
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Re: are small-wheeled tyres always a tight fit?

Postby Brucey » 9 Aug 2018, 8:21pm

re tight-fitting marathons; I was very worried recently when fitting some 16" marathons (349 size) that they would be a very tight fit on some old (Dunlop) 16x 1-3/8" rims. These rims have quite often ended up with tyres that do not seat correctly on them, i.e. it doesn't matter what you do, there is always a low spot, because the tyre is too tight for the rim. However to my great surprise the new marathon tyres seated perfectly and were not (in the grand scheme of things) super- difficult to deal with.

However, unfortunately, they are still slightly too stiff for my chum to squeeze and thus persuade the bead to sit in the rim well, so they cannot get them off again.

BTW a lot of modern rims don't have a proper rim well; they have a shallow recess. IME this means that it is more important than normal to maintain tension in the bead (eg using a tyre lever) as you push it into the centre, and if the tension is not maintained, some tyres immediately spring open and any slack generated is lost. Rims with square-sided rim wells are a bit easier to deal with in this respect.

cheers
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brynpoeth
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Re: are small-wheeled tyres always a tight fit?

Postby brynpoeth » 9 Aug 2018, 9:31pm

Could be worth warming the tyres, just leave them out in the sun maybe

If one uses a lot of brute force to get them on, could this damage them?
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Mick F
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Re: are small-wheeled tyres always a tight fit?

Postby Mick F » 10 Aug 2018, 8:03am

I've just remembered something with respect to the original Moulton rims versus the Sun CR18.
The original ones had a deep enough well, but it was very narrow. The "land" for the tyre beads was very wide.
The Sun CR18 has the same depth of well, but proportionally wider, and overall width about a millimetre wider too.

These combine to make the CR18 rims easier to fit/remove the tyres.
Mick F. Cornwall

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John1054
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Re: are small-wheeled tyres always a tight fit?

Postby John1054 » 10 Aug 2018, 8:13am

There's a useful video on Spa's web-site. It advocates using toeclip straps to hold the tyre in the well, whilst working on the opposite "hard to move" side of the wheel. I haven't yet had to replace or remove my Brompton's Marathon Plus tyres yet, so can't confirm if this method works?

igauk
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Re: are small-wheeled tyres always a tight fit?

Postby igauk » 11 Aug 2018, 12:35am

FWIW on my Alex DA16 20" (406) rims Schwalbe Pro 1's (installed tubed) were a complete nightmare irrespective of what method was used, including VAR levers and hands and straps. I think they'd be great on a tubeless compatible rim but the thought of trying to fit them out on the road means they're in the spares box. Schwalbe Duranos (wire bead) were pretty easy, same but with folding bead were okay. Easiest of all have been Panaracer Minits Lite which is fortunate as they've turned out to be fast, light, comfortable and grippy, a bit more rolling resistance than the Pro 1's but not by much and outweighed by the ease of installation. None of this is much use if you need a treaded tyre I admit!
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Brucey
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Re: are small-wheeled tyres always a tight fit?

Postby Brucey » 11 Aug 2018, 1:25am

interesting, a review of the minits tough tyre here

http://www.auntiehelen.co.uk/tag/panaracer-minits-tough/

suggests that this type is not great for punctures in the wet, but maybe the trike use and the flints locally paint it in a bad light (check out the flints in the marathons!). Like you say, no tread means they are unlikely to appeal to my chum but I might give them a go. They are currently on sale in Evans for £14.99 in 1.25" x 20" (406) size.

https://www.evanscycles.com/panaracer-minits-tough-tyre-00132162#modal__product-zoom-modal

Might make a good front tyre on a Moulton, with something a bit tougher at the rear (Durano maybe?)

cheers
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