Too many high gears on Hybrid - 50/34 compact

small_bloke

Hi, I have a too many high gears on my Boardman Hybrid Comp. I don't need to go 30mph when commuting with panniers. Some hybrids aren't that well designed when it comes to gearing.

Rear cassette - 11-32 I think or maybe 12-32
Chainset Double FSA Vero 50/34.

Whats the smallest outer chain-ring I can use. Maybe 48T or 46T?

Ideally I would also like to replace the cassette for very steep hills (heavier pannier days).
Replacing cassette with 12-34 or 11-34 would be nice but makes the gear range too wide for a nice cadence.
I would like 34 rear but is there anyway I can lose more high-end gears on the rear such as 11, 12, 13, 14 and still keep the 34 rear cassette for very steep hills.

I've looked at Sheldon Brown for reading but finding it hard to make any sense.

Help appreciated.

rubertoe

Start here

viewtopic.php?f=40020&t=12583566

nigglenoo

Are you sure about the rear cassette? I ask because the spec for the Hybrid Comp on Halfords website says 11-28T, but then it also says '16-20 gears' :roll: Presume it is 10 speed? If its 11-28T then the first option to get lower gears would be to try something like a 11-32T, but you will find steps between the gears get larger. Also you may need a different rear mech, though not sure TBH because its SRAM and I am not too familiar.

BTW with 11-34T usually the only difference from 11-32T is that the largest sprocket has 2 more teeth, all the other sprockets are the normally the same.

There are compact double MTB chainsets available, eg. a 42/27, or even 36/24T which would significantly lower the gearing all round, but you would probably need a new front mech for this and I am not sure what front mech you would need for the same reasons given above, plus there could be other issues such as whether the mech can be positioned low enough and still clear the chainstay, or whether the lower bottle boss would get in the way of the mech clamp.

EDIT: forgot another issue: chainline will be different on an MTB chainset...

Initialised

Dreaded double post

Initialised

I think you need a 46/30 on the front. You can probably get away with lowering the front derailer rather than replacing it and since it's bottom pull you won't risk needing a new gear cable. On the rear there should be no problems changing from 28T to 34T you may not even need to adjust your chain length, I think it's typically one link per tooth so you'd be dropping 4t from the front and gaining 4t at the rear.

gosport_commuter

I'd change the whole chainset as above - on my bike I was lucky enoughthat even though I had a double setup, I had a triple capable shifter, so for me I just put on an LX triple chainset and now I have gears that could climb walls! fantastic for commuting and dont spin out until over 30-32mph ish. also cos I left the road freewheel on the back I still have close ratios - so no massive jumps between gears.

Only caviat is to make sure you derailleurs are up to the job.

If you have shifters/derailleurs that can only handle something less drastic then I'd still try and opt for a lower geared compact chainset - look into wheter you can use a mtb one - I havnt any experience, but have heard that SRAM are very good for mixing and matching between road and mtb unlike shimano or campag.

small_bloke

Thanks all for your replies. I have double checked the casssette and its a 11-28T (Not 11-32 as I originally thought for some reason) . Best and cheapest option is to change this for a 12-32 but might need to change the chain as well.

Later I'll also look into changing the outer chainring from 50T to perhaps 46T to give me a better range of gears from the big ring. Hopefully 46T chainring will work with a 34T ring.

nigglenoo

What is your rear mech? It might not cope with the 32T

small_bloke

nigglenoo wrote:

What is your rear mech? It might not cope with the 32T

Rear mech looks medium or long cage SRAM X5. Definately not a short like the SRAM RIval on my road bike. Thanks for raising the point though.

nigglenoo

small_bloke wrote:

nigglenoo wrote:

What is your rear mech? It might not cope with the 32T

Rear mech looks medium or long cage SRAM X5. definitely not a short like the SRAM RIval on my road bike. Thanks for raising the point though.

Should work then, may even get away with keeping the chain, but check it for stretch as if its gone too far it will wear the sprockets out.

Initialised

If you go from 28T to 32T a medium cage should still fit, but you'll need to add two links to the chain (or avoid 50-32)

I've recently gone the other way, from 12-32 to 11-28 and find I climb better for having a lower ratio, but I don't tend to carry much extra weight (on the bike that is).

nigglenoo

Initialised wrote:

If you go from 28T to 32T a medium cage should still fit, but you'll need to add two links to the chain (or avoid 50-32)

Not necessarily, bikes often have a slightly longer OEM chain than they absolutely need, so worth just trying it as it is and checking its not tight in the 50/32 combination, though I still say check it for stretch as well.

apreading

The Boardman CX bikes come with smaller big rings - this would probably be ideal for you, especially if you also go for an 11-32 or 12-34.

Often on ebay but cant see one at the moment except the whole chainset: http://www.ebay.co.uk/itm/FSA-OMEGA-COM ... 5aea89b131

I reckon you could change the rings on the front and the cassette without changing anything else (although check chain length to be sure).

small_bloke

I found a FSA 46T outer chainring for £15 from Planet-X which is good value I think. However not sure if this is designed to work with a 34T inner ring. When i zoom into the pic it reads 36/46T?
I have a FSA Vero Compact 50/34 chainset 110BCD.

http://www.planet-x-bikes.co.uk/i/q/CRF ... _chainring

apreading

First let me say that I am not an expert, but my understanding is that this will fit fine with any inner ring designed for 110bcd (in other words compact chainset). I think it just says 46/36T because they have broken a complete chainset that had a 36 inner and are selling the rings separately - its not a compatibility thing.

gosport_commuter

Before I switched to a triple I had an FSA compact chainset with 46/36T rings. I changed the inner ring to 34T so it was now a 46/34 - as you are contemplating. It worked fine, no issues to report - as long as the BCD (bolt circle diameters) match you should be absolutely fine!

apreading

gosport_commuter wrote:

BCD (bolt circle diameters)

So thats what BCD stands for - I knew what it was but never looked up what the acronym stood for! thanks

At £15 I might even get one of those 46 rings myself - you never know, I might want it someday...

small_bloke

Thanks all for your help and advice, I received the 46T FSA chainring from Planet-X today (turned up mega fast for some reason). It's now fitted and working fine. There's quite a large vertical gap between front mech and large chainring e.g more than 5mm (obviously because 46T is smaller diameter than 50T) but still seems to shift fine. Don't want to lower the front mech as it leaves clamp marks in the paint.

The chain looks about 2 or 3 links too long, but I'll leave it for now incase I change the rear cassette from 11-28T upto 12-32T.

BTW, the FSA chainring from Planet-X is a great buy for £15. (+£2.50 delivery unless you spend over £20 it's free)

nigglenoo

Personally I would lower that mech to about 2mm above the chainring at the closest point, to avoid any derailment/trapping of the chain.

gosport_commuter

nigglenoo wrote:

Personally I would lower that mech to about 2mm above the chainring at the closest point, to avoid any derailment/trapping of the chain.

+1

oldwelshman

Started commuting 20 miles a day in new job, using my hack bike and got plenty of right closthing can anyone recommend a decent hi viz ruck sack? I dont want on eof thosde ruck sack cover things if if I can get a decent ruck sack

Initialised

The chain will be exactly 4T (2inches) too long, but this should only cause problems when cross chained running small sprockets on the small ring and on bumpy descents.

+1 to nigglenoo, drop the front mech a little to close the gap and reduce the chance of chain suck, drag, shifting issues as the rings and chain wear and the risk if losing the chain off the top of the big ring.