13T top cog on Shimano 10 speed

[Tompsk]

For my gearing a 50T x 13T top (104") is all I need but I can't find any 10 speed cassettes that do this. The only 13T top cog I can find available at the moment is an Ultegra 9 speed (e.g. from SJS), would this work or will the 9 speed spacing stop the gear being selected cleanly / at all?

I'm happy to mix and match cassettes but money is not endless here! Cassettes are about £12, cogs about £8. I'm actually putting 9 of 10 on a 7 (see Sheldon Brown for details) if that makes any difference.

I think Tiagra is the only current 10 speed (road) groupset by Shimano at the moment and that only starts at 11 or 12? I don't think any previous 10 speed groups had a 13T top cog???

Some current 9 speed cassettes (Sora or other groupset?) seem to start with bigger top cogs than 12 but (like legacy Ultegra 9 speed bits) the spacing may stop it working?

I have access to a milling machine, belt sander and lathe so could reduce the built in spacer that top cogs have, but I'd rather not go down that route!

Perhaps I will have to carry round the 'dead weight' 12T until 10 speed trickles down to Sora and a 13T is available then (or will Shimano thwart again any attempts to go away from their rigid idea of what everyone needs/wants/will have - don't get me started on that one!)

[NetworkMan]

On 7 and 8 speeed, and I think on 9 speed too,the cable goes slack in top gear and the correct selection of the top sprocket is determined by the derallieur limit screw. Often too, the spacing between top and second cog is not the same as between the other gears. If this is true of 10 speed then you have more of a chance though if, as seems likely, the 9 speed sprocket is wider then the system may not run so well when the chain is running at an angle.

I'm proposing to put a 13T 7 speed cog on top of an 8 speed cassette, but that is easier since the chains are the same width.

[cycleruk]

13T top sprocket is available but with only a 25T large cog and possibly more than you want to pay:-
http://www.rosebikes.co.uk/article/shim ... /aid:98472

The other thing though that sometimes happens is a larger 1st sprocket can cause the chain to catch the seatstay. (depends on the shape of the stay/dropout.)

An alternative is still to use a 12T cassette but drop the chainring down to 46T which should give about the same ratio.
That way you have a larger range of current cassettes such as 12/30 Tiagra etc.

[keyboardmonkey]

I'm actually putting 9 of 10 on a 7 (see Sheldon Brown for details) if that makes any difference.

So you have a 130mm 7sp (MTB) freehub? You don't mention how big you want the largest sprocket to be. If 30T is big enough don't you just need, say, a 12-30 cassette - Tiagra or Ultegra? (105 didn't offer that option last time I checked.)

On the picture below (sorry about the quality) the smallest 12T is next to the 13T on an Ultegra cassette. The 13T appears to be the designed to allow the lock ring to fit inside. (The 12T has a knurled surface against which the lock ring sits; the 13T seems to accept the lock ring inside it sufficient to allow you to tighten up the lock ring.)

Ultegra 6700 12-30 10sp cassette

I can't guarantee 100% that this will work, but when I fitted an 8-from-9 cassette on to my 130mm Deore DX freehub body I simply used a 13T 9sp lock ring and everything worked fine. Hope this helps.

[Ugly]

check out BBB cassettes much bigger range than shimano in 10 and 11 speed, I have them in campag configeration on two bikes and they run fine, not had them on long enough to know how they will wear

[Tompsk]

Thanks for the replies so far. Rose bikes do have what I'm looking for but at £20 inc. postage:

http://www.rosebikes.co.uk/article/shim ... aid:119159

(Looks like they are German despite misleading .co.uk suffix) Anyone know of a British distributor (for lower postage not anti German reasons).

I'm unsure of using a non-top cog next to the lock ring as the ridges on the cog provide a locking function, anyone tried this - perhaps with thread locking compound on the lock ring thread.

The gearing is for a 126mm OLN frame. A 25T to 28T bottom cog is all I need to go with a 30T front on a 3x 4603 Tiagra (purchased before realising the difficulty of changing the ring sizes). However the 50 39 30 ratios are fine if the cassette is 13-27ish.

[keyboardmonkey]

The gearing is for a 126mm OLN frame. A 25T to 28T bottom cog is all I need to go with a 30T front on a 3x 4603 Tiagra (purchased before realising the difficulty of changing the ring sizes). However the 50 39 30 ratios are fine if the cassette is 13-27ish.

Can I assume you will be using a 10sp chain?

How will you be changing gear?

This is do-able, I think, but perhaps as 8sp with 126mm at the back.

If I were you I would buy a Shimano Tiagra 4600 for £12.99 and batter out the rivets if 9-from-10 doesn't fit. Then discard the 30T. Use the 13T with the lock ring.

The tech docs describes the 13T thus:

Y1ZD1390N Sprocket Wheel 13T (Built in spacer type)

The wording "Built in spacer type" is the same as for the 11T and the 12T. There just isn't a dedicated 13T lock ring. 11T and 12T lock rings are quite different from one and other. I reckon the 13T "built in spacer type" would work with the lock ring that comes with the 12-30 cassette, but I understand your caution.

I'm unsure of using a non-top cog next to the lock ring as the ridges on the cog provide a locking function, anyone tried this

I have 126mm 6sp (Shimano 600 6207 hub) and 130mm 7sp (Deore DX hub). And a Tiagra 4600 cassette fitted to another bike. I can have a play about if you like. (Do you want to keep 10sp spacing on the cassette?) I would be interested to see what happens

[thirdcrank]

... The other thing though that sometimes happens is a larger 1st sprocket can cause the chain to catch the seatstay. (depends on the shape of the stay/dropout.) ...

This is an important consideration. When I made the giant leap from 6 speed freewheels to STI I made the same sort of gear inch calculations you have made and decided that a 14T small sprocket would be more than enough for me. IIRC the only way of achieving that and certainly the one I decided on was an Ultegra junior racing cassette. This was all for my retirement present to myself which included a new handbuilt frame. When they built it all up, the hub needed re-spacing to avoid the chain fouling the seatstay. I was a bit miffed because I had queried this possibility at the ordering stage. When the cassette needed replacing, I did what I should have done in the first place and fitted the mainstream offering with a 12T and achieved the lower gearing with smaller chainrings.

[Tompsk]

Chain, STI and front / rear changers all 10sp Tiagra.

I have a 12-28 10sp and will try using the 13T as top cog or leave out 14T to make a 9sp for a 7sp body. Probably buy 10sp 130mm wheel in long term.

[ChrisButch]

check out BBB cassettes much bigger range than shimano in 10 and 11 speed...........nothad them on long enough to know how they will wear

Poorly, unfortunately, I think you will find. I experimented with them when trying to find a cheaper alternative to Marchisio custom cassettes, soon gave up.

[Tompsk]

Thanks for all the help.

I have built a 9 speed cassette from a Tiagra 10 speed 12-28 by just leaving out the 12T and screwing the lock ring onto the 13T cog. This fitted perfectly onto the 7 speed 105 hub and into a 126mm OLN steel frame (using a 10speed chain). Just to show you don't have to believe everything the manufacturers put out this has worked with no snags at all with the original set up on the bike which was old campy 144mm chain rings, a 9 speed Tiagra rear derailleur and friction shifters.

I have since put in a Shimano 501 10 speed hub with 10 speed cassette (12-27) into the same frame and this works perfectly too with the above set-up

The above wheel with 9cogs of a 10 speed cassette on a 7 speed body has also worked perfectly on another (steel frame) bike with SRAM APEX 10 speed group set with the highest gear setting on the levers adjusted out by setting the limiter screw on the APEX rear derailleur to the 9th (13T) cog.

YMMV

[Keezx]

With Miche cogs you can build yourself anything you like with loose cogs.
Economical too, change only the worn ones.