Moulton Gearing Advice ?

[Christine]

Due to not having the space in my car or caravan for my full size tourer I am getting a Moulton.
Now it has 34 as the smallest chainring on the front & an 11 to 25 block. But I like low touring gears & am wondering what would be suitable for the large sprockets on the back ? I realize with the wheel difference size it will make a difference with the gears, but by how much I am wondering ?
Any help would be greatly appreciated, thanks,
Chris

[Brucey]

traditionally you can work out gears in 'inches' which corresponds to the effective wheel diameter, were the pedals connected directly to the wheel.

So if you (say) use a 46 chainring, 23 sprocket, and a 26" wheel, the gear is (46/23) x 26 = 52"

If you know what gears you would use with 27" wheels, you can work out how these compare with Moulton gearing quite easily. So for a 28-406 tyre you would need a 16T sprocket to get a 52" gear using a 46T chainring.

There are several calculators (eg this page http://www.bikecalc.com/gear_inches) that will allow a suitable comparison to be made.

cheers

[Christine]

Oh thank you when I was in my younger years I knew the way to work it out but had forgotten & just couldn't find anything on the internet.
The shop I am buying it through didn't know either, although knew what I was talking about.
Probably don't get customers very often who know what they want exactly !
Many thanks,
Chris

[simonineaston]

Assuming you have a TSR (only guessing!) those sprockets will give you a low of 25", I think, and that might not be quite low enough for you if you like low gears. What would be helpful to you is to see if you can find out what sprockets you had on your full-size tourer and what lowest gear that'd give you. Then decide whether you need to make any changes to the gearing on the TSR - it might be a bit of a problem finding a chainring smaller than 34 teeth, though, so the only practical solution would be to pop another block on with a different range, 11-34 for example, which would drop you down to about 20" for your lowest... lightweight gear blocks are about £20 and up I think.
A few months on the Moulton and you'll be wanting to sell the 'old-fashioned', too

[AM7]

I'm guessing that you're talking about the Campagnolo equipped TSR30, which comes with an 11-25 cassette and 58/48/34 chainrings to give a gear range of 25-98 inches. I have one and I love it but as others have said, whether the 25" low gear is low enough for you is something only you can decide.

However, lowering the gears further on a TSR30 isn't as straightforward as putting a wider range cassette on the back or a smaller chainwheel at the front, especially if you wanted to keep the gears at the top end. This is because the existing front and medium cage rear mech are already at the limits of their capacity; and AFAIK Campagnolo don't make a wider range 10 speed cassette with an 11 tooth top sprocket than the 11-25. To add to the fun, the chainset isn't a normal triple, but a double chainset with a third ring bolted to the inner ring.

So while it is possible to alter the gearing, it wouldn't be without a degree of complication and expense (of having to change one or more components). I would say that if you really need lower gears than the stock TSR30 has, you might be better off with a TSR27 which has a gear range of 20-108 inches.

[Brucey]

I suspect that if it is as AM7 describes, the rear mech is at the limit of total capacity but not at the limit of max sprocket size. If so, you should be able to fit a longer (by one complete link) chain, a 28T sprocket (from another cassette) and lose one of the smaller sprockets you don't use much (eg a 12T perhaps?).

The downside to this arrangement is that the chain will run slack on the small-small combinations where it didn't before. But since these are normally duplicate or near-duplicate gears anyway, you don't have to use them. Some folk get on Ok with this setup, or only use it when they are carrying a load someplace hilly.

cheers

[Christine]

Thanks all, food for thought !
Yes it is a TSR 30 I have ordered, prefer drop bars, probably won't use the big front ring as I once in a blue moon only do on my present touring bike.
The Moulton is a 'needs must' with lack of space if I am using my mini caravan.
I had worked out I would like a 34 large sprocket if I am able !
Chris