11sp cassette / 9spd freehub / Sturmey X-RDC

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speedsixdave
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11sp cassette / 9spd freehub / Sturmey X-RDC

Postby speedsixdave » 10 Jan 2020, 11:03pm

As part 4007 of the slowest upgrade programme ever, I think I'm about to order a Sturmey X-RDC rear cassette hub brake, in an attempt to solve the rim overheating issues previously discussed here.

Currently the bike - a Moulton Jubilee - is running Shimano 105 11-speed (53/36 x 10-32). I don't really want to change the 11s STI levers & mechs. As I understand it the X-RDC cassette hub is 8-9speed compatible which means it can also take a 10spd Shimano cassette, but is not '11-spd compatible'.

I am looking for the best option for a cassette to work with this set-up, and 11-34 would be perfect for mountain touring. Shimano's website suggests that the CS-HG700-11 cassette will fit both 11- and 10-speed freehubs. Does this mean it will fit the X-RDC? I realise this is specialist knowledge! What are my next best options if this is not likely?

Thanks as ever!
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Brucey
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Re: 11sp cassette / 9spd freehub / Sturmey X-RDC

Postby Brucey » 10 Jan 2020, 11:23pm

I feel somewhat remiss in that I have not tried this combination despite having access to the relevant parts. There are two potential issues

1) fitting the cassette onto the freehub body and tightening the lockring
2) whether the 11s bottom sprocket comes too close to the spokes; it is slightly further leftwards than a 10s one.

I don't expect the former to be an issue; I think that SA have reproduced the Shimano spline etc such that there are no significant differences in 'fit' on the freehub body.

I have tried that cassette on a set of 130mm OLN wheels (normally used with a 10s cassette) just to see how close the RD came to the spokes. 'Closer than normal' was the answer, but not by much. In fact the wheel had aero spokes so the clearance was a bit more than I expected; the RD was clear of the spokes by about 2.5mm, maybe a touch more. A 135mm wheel (or one with a smaller rim) would be better than that. However you would lose 1mm of that clearance with round spokes and maybe flange positions etc on a different hub might vary it +/- another 1mm or so.

What I do think is that with many setups of this sort, if the chain derails inwards off the big sprocket, this is what can precipitate the mech getting dragged into the spokes. Thus having the mech close to the spokes is certainly part of the problem but it isn't the whole story by any means.

BTW if the chainstays are angled unfavourably, you can run out of clearance between the brake plate and the chainstay on the left side. This is more likely with small-wheelers, because the chainstays are -all else being equal- usually more angled.

IIRC you can also space the hub down to ~130mm OLN but this means even less clearance on the left side.

cheers
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mattsccm
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Re: 11sp cassette / 9spd freehub / Sturmey X-RDC

Postby mattsccm » 11 Jan 2020, 11:26am

Probably a bit excessive for your purposes but there are two options for fitting standard 11 speed cassettes on to a 10 speed hub. I grind a bit of the end of each ridge on the free hub. About 1.5mm works although I am not picky about this. It does move the lot closer to the spokes though. If it is too much stick a spacer back in. Those who don't want to grind expensive hubs have the cassette machined instead. Both works, the former is cheaper. Just watch the spokes.

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speedsixdave
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Re: 11sp cassette / 9spd freehub / Sturmey X-RDC

Postby speedsixdave » 12 Jan 2020, 8:39pm

Thanks very much gents. Spa Cycles have that cassette on special offer at the moment so I'm going to give it a go. Will report back with findings, but it may take a while!
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scottg
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Re: 11sp cassette / 9spd freehub / Sturmey X-RDC

Postby scottg » 13 Jan 2020, 8:05pm

The direct answer is the 11-34 in your post, has the large sprocket dished,
the overall width of the cassette is the same as a 9/10 speed cassette,
so it fits your hub, no grinding required.

The 11-32 and smaller, 14-28 etc, cassettes are wider, and only fit the 11 speed hubs.
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speedsixdave
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Re: 11sp cassette / 9spd freehub / Sturmey X-RDC

Postby speedsixdave » 14 Jan 2020, 9:41pm

Thanks Scott, that's very helpful. The cassette is now on order, the hub will be shortly!
Big wheels good, small wheels better.

Two saddles best!

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speedsixdave
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Re: 11sp cassette / 9spd freehub / Sturmey X-RDC

Postby speedsixdave » 14 Feb 2020, 8:03pm

I am finally getting somewhere with this! My Sturmey X-RDC arrived from SJS yesterday, built up into a 36h 406 wheel on a Sun CR18 rim. Unfortunately SJS would not re-space the hub to 130mm so have built it as a 135mm wheel and I will have to deal with that along the way. Also on the downside the hub came with absolutely no fittings whatsoever except for axle nuts. So I still need to order a brake cable adjuster (HSB422, £5.99 plus postage) and a pinch bolt assembly (HSK770, £1.99) to go with the brake arm clip (HCB101, £2.99) I did remember to buy. All of which makes the 'sale price' of £49.99 for the hub slightly less of a bargain. 6/10 so far.

The good news, however, is that the Shimano CS-HG700-11 11-34 cassette fits perfectly on the X-RDC freehub. I've not yet tried it with a derailleur and chain etc but the gap between 34t sprocket and spokes looks pretty decent, so I'm not too worried about that. With a 56/39 chainset that will give a range of gears from 20.8" to 92.5", fine for a touring bike, and reasonable cruising gears in the 13, 15 and 17 sprockets.

Some steps still to go but at least the gears should work!
Big wheels good, small wheels better.

Two saddles best!

Brucey
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Re: 11sp cassette / 9spd freehub / Sturmey X-RDC

Postby Brucey » 14 Feb 2020, 8:55pm

the only way you can respace the hub from to 130mm is by robbing whatever space you can on the RHS (scope for which depends on the cassette used and the details of the frame, but will in any event be very limited with an 11s cassette in use) and taking the rest from the LHS. If you take 5mm out of the LHS then the brake fittings will start to foul most frames. The dish on the wheel is liable to be a bit poor too; the NDS spokes will certainly need threadlock. Anyway it is no surprise to me that SJS wouldn't respace the hub; sight unseen of the frame it is going into, it would almost certainly be wrong somehow.

FWIW full price hubs of this sort, boxed, come with all the fittings as well as a brake cable/adjuster. It does mention that you 'only get axle nuts' with this hub on SJS's listing, but only in the Q/A, not the main description.

cheers
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speedsixdave
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Re: 11sp cassette / 9spd freehub / Sturmey X-RDC

Postby speedsixdave » 15 Feb 2020, 8:39pm

Am pleased to report that the 135 wheel just squeezes between the dropouts of my Jubilee, so we are getting somewhere! The brake side has a massive nut about 5mm thick and I reckon I could get a mm off the drive side without calamity, so I think I will try and thin it down by 2mm or so overall to take a bit of pressure off the rear triangle.

I did read the question on the SJS site about the lack of fixings but at the back end of last year, and had completely forgotten about it when I ordered the thing. My fault for a lack of attention, but it still seems a bit of a cheap trick. Caveat emptor!
Big wheels good, small wheels better.

Two saddles best!

Brucey
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Re: 11sp cassette / 9spd freehub / Sturmey X-RDC

Postby Brucey » 15 Feb 2020, 8:59pm

it has always been difficult for SA (or any hub manufacturer) to know what to supply with hubs. The reason being that hubs are bought for three different types of customer application;

a) OEM new builds
b) Aftermarket new builds
c) repairs

With a) they want fittings, but a bare minimum to suit their specific needs; they don't want a factory full of alternative 'just in case' fittings left over. packaging needs to be plain, simple and minimal. With b) the (fancy retail) box comes with a standard selection of fittings, with the result that there are usually bits left over. For example most boxed SA hubs come with a brake cable suitable for flat bars, but also a solderless nipple (for the brake end) so you can cut the extant cable, so it can be fed through a braze on fitting. Since the two cable ends replicate the two most common lever fittings, the cable you get can usually be used with any lever, provided you cut the right end off. With c) you don't want any fittings at all; normally you are re-using the old ones. Again simple packaging is the usual thing.

By those standards you are a type b) customer but bought a type a) or type c) hub. With a type b) purchase, there is a kit of parts you need in a bag; sadly they don't seem to sell that kit of parts separately.

cheers
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