How good/strong are Brompton wheels/rims?

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mercalia
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How good/strong are Brompton wheels/rims?

Postby mercalia » 5 Jun 2016, 8:03pm

How good/strong are Brompton wheels/rims?

good enough for a heavy person touring, with a large bag on the front? will they really take the punishment. The ones I have seen dont look that high quality.

Brucey
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Re: How good/strong are Brompton wheels/rims?

Postby Brucey » 5 Jun 2016, 8:29pm

there are currently two sorts on offer;

- a single walled rim
- a double-walled rim

I think either is 'strong enough' for touring purposes but the double-walled rim is probably stronger in several respects. The braking surfaces are not vastly different in thickness.

The unknown in my mind is if the double-walled rim has any tendency to crack round the spoke holes (many types do).

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Orangey
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Re: How good/strong are Brompton wheels/rims?

Postby Orangey » 5 Jun 2016, 9:01pm

Not directly wheel related, but worth bearing in mind that according to Brompton the maximum recommended weight for rider and luggage is 110kgs. Depending on how heavy "heavy" is, that may be a factor - https://brompton.zendesk.com/hc/en-us/articles/203296301-What-is-your-recommended-maximum-rider-weight-. The official limit on the front luggage is 10kg which is probably conservative, but worth considering.

I've not noticed any issues with my double walled wheels - either the ones I built myself, or the factory built ones, after a couple of years. But I'm not touring, only commuting, and I weigh around 76kg so not huge, but not tiny either.

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Tinnishill
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Re: How good/strong are Brompton wheels/rims?

Postby Tinnishill » 4 Jul 2016, 6:13pm

Sorry for the slow reply, I've just noticed the thread.

My spouse and myself have been doing several multiday tours a year on a pair of T5 Bromptons since 1998. She is svelte and I'm 90+ kgs. When camping I could be carrying up to 20kgs of luggage. The extra mass and small rims means that the rims wear out faster than might be expected by someone used to standard touring bikes; monitoring the rim wear indicators is the answer to that problem. Clean the rims and brake blocks now and then. Replacement rims are available as Brompton originals, Velocity Aeroheat Machine Side Wall or Sun CR-18. Avoid the Sun rims, they have a good build quality but are a couple of mm wider diameter than normal and eyewateringly difficult to get tyres on. Brompton rims are only available for 28 spokes but now come in two sorts, "angle drilled" for hub gears and standard drilled for other hubs. My guess is that if you weigh less than 80kg they should be fine. Being of a stouter persuasion I was initially plagued by broken spokes on the back until I had a new rear wheel built with 36 spokes, which cured that vexation. The lithesome spouse didn't have a problem.

Cheers.
Agitate, educate, organise.

ambodach
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Re: How good/strong are Brompton wheels/rims?

Postby ambodach » 5 Jul 2016, 7:49am

Since standard Brompton rims and presumably hubs come with 28 spokes where did you get the 36 hole ones built? Wheels are not my field and the possibility of broken rear spokes bothers me.

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Tinnishill
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Re: How good/strong are Brompton wheels/rims?

Postby Tinnishill » 5 Jul 2016, 11:22am

Howdy,

A 36 spoke wheel on a 349 rim is a matter of finding a wheelbuilder who is willing to do it for you. Finding a convenient wheelbuilder depends on where you live. Most cities will have a few wheelbuilders. I live out in the sticks, turning a visit to a big bike shop into an expedition. At the moment you can get Velocity 36h 349 rims from a couple of web dealers, but stocks often come and go. You would also need a 36h hub which fits the 110 over lock nut dimension of the back of a Brompton. You might not need the 36 spokes, you might be lighter than me and my junk. The factory wheels have changed a bit in the nearly 20 year since I bought mine, particularly the "angled" spoke holes they now do. Anyway, you can't buy a Brompton minus the standard back wheel, so I would just try it and have a fall back plan in case of trouble. Carrying a kevlar temporary spoke gives a bit of reassurance. Touring with a combination of Brompton and train has been a lot of fun.
Agitate, educate, organise.

ambodach
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Re: How good/strong are Brompton wheels/rims?

Postby ambodach » 6 Jul 2016, 8:10am

Thanks for that. I am considering a trailer to cut carried weight on the wheels. I also live out in the sticks so no wheel builders handy.

Brucey
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Re: How good/strong are Brompton wheels/rims?

Postby Brucey » 6 Jul 2016, 11:04am

ambodach wrote:Since standard Brompton rims and presumably hubs come with 28 spokes where did you get the 36 hole ones built? Wheels are not my field and the possibility of broken rear spokes bothers me.


spokes are easy enough to change, although in small wheels like Brompton ones it may seem odd to have to put a gentle bend into them in order to fit the 'inside' spokes; the bend will largely disappear when the spoke is tensioned, (and can of course be helped to disappear with a push or two).

Brompton wheels are (IIRC) usually built 'unbraced' which means that the spokes are free to resonate, making gauging the tension fairly easy. Moreso than in larger wheels, replacing a spoke is usually just a question of tensioning the new spoke so that it matches the others. If you simply do this, the wheel will usually be straight enough.

If in doubt, (and you carry a smartphone) perhaps you could make a recording of the way the spokes sound normally (when struck with a screwdriver or something) and use that as a point of reference. If you are carrying a heavy load on tour, it is a good idea to check for loose spokes once every few days anyway.

The only other wrinkle is removing the sprockets on the rear wheel to allow access in some cases. Again this usually isn't difficult; eg on SA hubs it is simply a question of prying a spring clip off with a small screwdriver. If you familiarise yourself with this ahead of time, it will hold no fears for you when you have to do it 'in the field' as it were.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

ambodach
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Re: How good/strong are Brompton wheels/rims?

Postby ambodach » 6 Jul 2016, 8:10pm

Thanks for that Brucey. I have changed sprockets on SA hubs fairly often but sometimes they just seem to be stubborn.Heretic that I am I had SA hubs on my Flying Scot in the 1950's for touring tho' I would never attempt poking inside.I check the tension on the Brompton wheels by striking with a metal tyre lever to make sure they all sound the same.I did straighten a twisted wheel once on N.Uist enough to continue my tour. Don't ask how it got twisted :roll: .

mercalia
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Re: How good/strong are Brompton wheels/rims?

Postby mercalia » 6 Jul 2016, 9:47pm

Brucey wrote:
ambodach wrote:Since standard Brompton rims and presumably hubs come with 28 spokes where did you get the 36 hole ones built? Wheels are not my field and the possibility of broken rear spokes bothers me.


spokes are easy enough to change, although in small wheels like Brompton ones it may seem odd to have to put a gentle bend into them in order to fit the 'inside' spokes; the bend will largely disappear when the spoke is tensioned, (and can of course be helped to disappear with a push or two).

Brompton wheels are (IIRC) usually built 'unbraced' which means that the spokes are free to resonate, making gauging the tension fairly easy. Moreso than in larger wheels, replacing a spoke is usually just a question of tensioning the new spoke so that it matches the others. If you simply do this, the wheel will usually be straight enough.

If in doubt, (and you carry a smartphone) perhaps you could make a recording of the way the spokes sound normally (when struck with a screwdriver or something) and use that as a point of reference. If you are carrying a heavy load on tour, it is a good idea to check for loose spokes once every few days anyway.

The only other wrinkle is removing the sprockets on the rear wheel to allow access in some cases. Again this usually isn't difficult; eg on SA hubs it is simply a question of prying a spring clip off with a small screwdriver. If you familiarise yourself with this ahead of time, it will hold no fears for you when you have to do it 'in the field' as it were.

cheers


this has definitely put me off getting a Brompton, back to the drawing board :lol:

Brucey
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Re: How good/strong are Brompton wheels/rims?

Postby Brucey » 6 Jul 2016, 10:24pm

mercalia wrote:
this has definitely put me off getting a Brompton, back to the drawing board :lol:


eh? It isn't much different to lots of other bikes, in a touring context. Better than many, in fact.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

ambodach
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Re: How good/strong are Brompton wheels/rims?

Postby ambodach » 7 Jul 2016, 7:45am

I should add that the taco'd wheel on N.Uist was not the Brompton but a 27in. rim. Had to stand on it to get it kind of straight before fiddling with the spokes. Brampton so far has been OK.