Is there a 14t end sprocket for SRAM 10 speed cassette

skiddlydiddly

Hi all. I started cycling again in the summer after a 23 year break. Things have certainly moved on a lot.

I was given a(too small at 19 inch frame) specialised rockhopper, which I used as a test to see if I was going to stick at it. I found I enjoyed cycling more than ever and loved servicing the bike, replacing first the chain, then rear cassette and middle chainring, bleeding brakes and fitting new pads, changing tyres and especially setting the bike up to the best fit for me.

Anyway, I decided that it was worth buying a new bike that actually fit me, and settled on the Boardman mx comp. Overall I'm happy with it, but the 48t/32t front rings and 12-36t(12,13,15,17,19,22,25,28,32,36) cassette are wasted on the speeds I'm doing-I pootle along at 15mph on a trail and can pedal up to about 25mph on the road. I like things to work the best they can for me and although I don't have any engineering qualifications, that's very much how my brain works. This leads me to think that the 12 and 13t sprockets are dead weight on my bike and if I could start the cassette off with a 14t and also slot a 16t in there to make it 14,15,16,17,19,22,25,28,32,36 it would suit my needs better than the existing ratios. This would give me similar speeds but with a straighter chainline and at a more comfortable cadence for me.
Another option is to find a 42t front ring to replace the 48t which would give similar results but after hours spent on google I am struggling to find one that I know will definitely slot straight on. I did try the shimano 42t top ring off my specialised just to see if it was machined close enough to fit, but although the pcd is the same at 104mm, the recessed curve in it is too small for my sram crank spider.

rockmonkeysc

You might have to fit road cranks to achieve what you want.
You can't get the 14t you want and mountain bike transmissions aren't really designed to give the ratios for road speeds

supersonic

Do you ever us the 32 and 36 cogs?

skiddlydiddly

supersonic wrote:

Do you ever us the 32 and 36 cogs?

I do. Not every ride but certainly more than the 12 and 13t sprockets which only rarely get used on downhills really. I'm guessing you might recommend the 12-28? I have looked at that as an option as I could probably manage the hills on a 28, but it would still have 2 gears I don't use when on the 48t ring.

jimothy78

I think the reason you're not using the smaller sprockets on the cassette is because your chainrings are so large - 48/32 is very big for a mountain bike. If you're worried about "dead weight" then remove the 48T chainring, left shifter and front derailleur, and run it as a 1x10 - you'll then need to use the smaller sprockets to achieve top speed - you might even find you need a (slightly) larger single ring.

The Rookie

Miche make a Shimano compatible 14T 'smallest' cog, you can then mate this to a cassette made of 2 different ones to get a sensible spread of ratios up from that
http://www.ebay.com/itm/Miche-Shimano-1 ... 58b0eae44d

jimothy78

The Rookie wrote:

Miche make a Shimano compatible 14T 'smallest' cog, you can then mate this to a cassette made of 2 different ones to get a sensible spread of ratios up from that
http://www.ebay.com/itm/Miche-Shimano-1 ... 58b0eae44d

This may be true, but hand on heart, do you think that's his best option?

Skiddly Diddly - have a look at the chart below.



The central part contains all the gear ratios your current setup allows you. I've highlighted in red those high gears that you say you don't use and the low gears you admit to using rarely (and as your fitness increases, you're going to use those ones less and less).

Furthermore, in yellow, I've highlighted the overlap (ratios available using the big ring that are also covered by the smaller one).

Notice that the remaining (non-highlighted) gears number exactly 10 - so from your 20 available gears, only 10 combinations are actually needed.

Now look at the column on the far right - it contains the gear ratios you would get if you replaced your existing double chainrings with a single, 38T ring. Notice how it includes 10 distinct gear ratios, no duplicates, and all in the range you need.

skiddlydiddly

Thanks for the replies .

Jimothy78-When I said dead weight, i meant more a waste of space and oppurtunity, rather than actual weight saving. I had looked for a 42t front ring to swap my 48 for but am not confident enough that the machining on the back face will fit my spider to take a gamble and buy it blind.
My fitness has increased defnitely, in a relatively short amount of time, Combine that with shedding approx 15kg it's just got easier and easier to pedal.
I basicly want to cruise at 15mph on the trails as there are people walking dogs, horses etc and the people I ride with are of varying levels, so even though I could go faster, they can't necessarily. The 25mph on a flat road is what I'm comfortable with speed-wise, taking into account what muppets drivers can be. That's what I based my requirements on. The chart is interesting though, I knoew there would be overlap, but not so much.

TheRookie-thanks for the link. Are miche a reputable brand?

jimothy78

skiddlydiddly wrote:

I had looked for a 42t front ring to swap my 48 for but am not confident enough that the machining on the back face will fit my spider to take a gamble and buy it blind

If going to 1x on the front, you replace the middle ring (or in your case, the 32) and as long as the BCD is the same, any modern chainring should fit. - What chainset is on there at the moment?

skiddlydiddly

jimothy78 wrote:

skiddlydiddly wrote:

I had looked for a 42t front ring to swap my 48 for but am not confident enough that the machining on the back face will fit my spider to take a gamble and buy it blind

If going to 1x on the front, you replace the middle ring (or in your case, the 32) and as long as the BCD is the same, any modern chainring should fit. - What chainset is on there at the moment?

It has a SRAM Via Centro 48/32t on. I tried a shimano 42t outer ring but it didn't quite fit. I can see how the inner ring would be better as it looked like a flatter face.

The Rookie

The bolts will fit, sometimes the shoulders used to centre the ring are a bit out, a little filing soon fixes that.

jimothy78

Looking at pictures of that crankset, it looks like the large, 48T ring is fitted on the inside of the spider - that's the usual way of fitting for a middle ring, not an outer ring, which might have caused some interference problems if you tried to replace it with a 42T outer ring (which is designed to mate onto the spider from the opposite side).

You should be able to source a 38T middle ring (or better still a single-specific ring), but first double check the BCD of your existing rings - measure from the centre of one bolt hole to the centre of the hole diagonally opposed to it.

skiddlydiddly

I thought about getting the belt sander out for a little "finessing". I decided not to as the holes seem slightly oversized and the centring shoulders obviously helped it line up and keep it true when pedalling.

The ring is a 104mm as I recently ordered a replacement middle ring for my specialised and the holes fit ok, just the facing was different around the holes, maybe 1mm too much material

skiddlydiddly

I've just tried old the 32t 104mm shimano deore middle ring I replaced and it does fit .

I'm not sure about going single ring yet though, might try and see if there are some oddball larger middle rings first and go from there.

skiddlydiddly

I've found this 42t one at £45 http://www.amazon.co.uk/Truvativ-Chainr ... +42t+104mm

It has the pin to stop the chain sliding onto the crank and seems recessed to go on the inside of the spider.

Then there's this one at £21 but it looks like it might be for a single ring. http://www.amazon.co.uk/Truvativ-Chainr ... +42t+104mm

Are the single rings compatible with a double, or are the teeth profiled differently seeing as they don't need to shift the chain?

jimothy78

skiddlydiddly wrote:

I've found this 42t one at £45 http://www.amazon.co.uk/Truvativ-Chainr ... +42t+104mm

It has the pin to stop the chain sliding onto the crank and seems recessed to go on the inside of the spider.

Then there's this one at £21 but it looks like it might be for a single ring. http://www.amazon.co.uk/Truvativ-Chainr ... +42t+104mm

Are the single rings compatible with a double, or are the teeth profiled differently seeing as they don't need to shift the chain?

You've provided the same link twice, there.

As for your final question - you've guessed it - single rings tend to have longer teeth to hold the chain more securely and lack shifting "ramps" to enable smooth shifts.

I'm still not sure about your plan of replacing just the outer of the two rings - the closer they are in size, the more overlap you're going to end up with. Especially as, if you decide to go single-ring later, a 42T is likely to be too big, you're spending a lot of money to achieve very little. I think you'd be better off going for the 38T (or 36T if you're worried about being underpowered for climbing) single ring, especially as they can be had for so little money, and if you don't like it, you can always go back to what you've got now.

http://www.chainreactioncycles.com/fsa- ... -prod28192

skiddlydiddly

I'd still like keep a straighter chainline on lower gears for hills. I don't like to hear the chain and atm on the big ring and lowest gear I can, even after fettling due to the angle of it.
I might try a 38t and raise the front derailleur(in case I accidentally click it out of habit), that way I can very quickly go back to the original setup.

jimothy78

skiddlydiddly wrote:

I'd still like keep a straighter chainline on lower gears for hills. I don't like to hear the chain and atm on the big ring and lowest gear I can, even after fettling due to the angle of it.

But what you're almost certainly hearing, at that sort of angle, is the chain catching on the edge of the front derailleur cage. No derailleur, no noise.

I realise I'm sounding like a stuck record (and feel slightly hypocritical, too, as I use a 2x10 setup myself), it's just that everything you said in your first post makes me think a 1x10 would suit you and your type of riding perfectly.

skiddlydiddly

For anyone who ever searches a similar thing, I ended up ordering an SRAM pg1050 11-32 cassette, which has 11,12,14,16,18,20,22,25,28,32 and a Miche 14t end/first sprocket.
This will give me a range of 14,15,16,17,18,20,22,25,28,32 when combined with my existing pg1050 12-36 cassette. This is pretty much spot on what I was after. There seems to be discrepancies with what SRAM and various sellers say the teeth count is, so I'll have to wait and see when they arrive.
There's also the option to tinker about with the gearing a little more if necessary, with having spare sprockets left over.

Thanks for the advice and links to the miche end sprocket.

Edited-the SRAM pg1050 11-32 cassette ratios listed on sheldon brown's site(and some others) are incorrect so of no use to me. I've now ordered individual replacement16t and 18t shimano 6600 sprockets from sjs cycles. Fingers crossed.
The miche 14t end sprocket took around 2 weeks to come from America and I now have 14,15,16,17,18,22,25,28,32,36. The derailleur cable and jockey wheel needed adjusting to suit the larger end cog. Then it just needed indexing again and it runs smoothly on the stand. Not been out for a ride yet though.

Edited. Have ridden it and the shimano ultegra 6800 sprockets work fine on the sram cassette, very smooth. As I removed the 12t and 13t sprockets, both of which had a machined spacer on them, I had to use an old plastic shim (from an 9 speed shimano cassette I already had) on the second to end sprocket. All it needed was me to trim off the little plastic locating dowels.