Help I need smaller gears - what can I do? A GUIDE

John.T

You can extend the chain using a powerlink but you would still need the other half of the link. I used to change between a compact and a standard chainset by having 2 shortish lengths of chain and 2 powerlinks. I just fitted the relevent bit of chain. I would not recommend having 2 powerlinks together. It may be fine but it just seems wrong to me.

185nick

Thanks John, great help I agree with your theory about having 2 powerlinks together. Think I'm going for the cassette option

joeyp101

has anyone considered the opposite?

can you get a sprocket lower than 11T? ie a cassette like 10-23 or 9-23?

John.T

Not in any normal set up.

Lunty

I'm currently running a Shimano 105 double front end with 53/39 tooth chainrings. Looking to convert (at least temporarily for attempting the Hardknott with some friends) to a compact-type set up. Could I simply buy a 34T ring, stick it on and expect everything to run smoothly?

What do I need to consider regarding 104/110/130 measurements?
From some basic searching there doesn't seem to be a 105 34T ring, could I just stick a Sora (or other model) on? (would be switching back to my 39 after the Hardknott so durability isn't much of a concern).
Rear cassette is 9 speed (Dura Ace), what impact does this have to the front end set up?

Preferably (cost wise) I wouldn't be replacing the 53T, would this cause any problems with the front derailleur?

Any other points I should consider are welcome.

Thanks!

John.T

Your current cranks have a 130mm bolt circle diameter (BCD). The smallest ring you can fit on them is 38 teeth. Compact cranksets have a BCD of 110mm which will take rings down to 33 teeth.
Tha maximum gap in the rings for a double front mech is 16 teeth so keeping the 53 would be a non starter anyway.
Your cheapest options are either a cheapish compact chainset that will fit your current BB with a 12/27 cassette, or a larger cassette, say 12/32 or similar with an MTB rear mech. You would also need a new chain. The latter would give rather large gaps between gears and probably cost more.

Surf-Matt

Or just pedal harder...

John.T

Surf. Can we please try to keep these stickies factual. Plenty of room for levity in the rest of the forum. You are right though.

blorg

@Surf- there are good reasons for wanting lower gears, griding away in a difficult one is generally not the most efficient way to climb a hill. If you can sustain a high cadence on 39-23 going up an extended climb then you should probably consider turning pro...

Unless you can ride up a mountain at the pace a pro does in the Tour why would you choose the same gearing as them? Just back from the Marmotte where triples were rather more common than you see in Irish sportives, and the guys riding them were not slow going up hills... I was on 34-27 and I needed it, not so much on the first climb but sure did on the Galibier and the Alpe d'Huez.

Ripley

Hope I'm in the right place to ask this...soon going on first solo loaded tour to France. Anything I've learned about bikes is from these forums. I know my existing setup would mean a walking tour of France.

I currently have Tiagra front chainset - 50/34 compact - 170mm cranks - Tiagra front D/R.
On the back we have Shimano 105 12/25 cassette. I have a Genesis Vapour cross bike.

To get lower gears two options:
a) install triple chainset. The tiagra shifters will handle a triple. Sounds like I know what I'm talking about - just about.
Do I need new f/derailleurs? Is there such thing as a touring triple? New chain?
b) Use an MTB 12/34 cassette. Do I need to replace the 105 d/r? New chain? Anyone recommend a robust/reliable derailleur and a good MTB cass, I would pay for quality/reliability. I must say b) sounds easier.
Any help greatly appreciated...Tks, James

Onan

Hello. I wonder if anyone with specific knowledge and/or experience of my setup knows what my options would be for achieving lower gearing.

It's a 9 -speed double - shifters, rear and front mechs, chainset, and cassette are all shimano tiagra.

My chainset is a 52/39 double.
My cassette is 11-25
The rear mech is short cage.

Does anyone know if I could go to a compact withouth having to change the front or rear mechs?

I'm assuming a triple is out of the question without changing rear mech to a long cage.

It may be a stupid question, but are chainsets made all in one piece, or can one just exchange one ring for another? If so, would keeping the 52, and changing the 39 for a 34 or 30 not solve any problems with the front mech?

My ideal would probably be to go to a 52/34 if such a thing exists, as I like my big gears for going down hills, but am totally unable to get up anything other than short hills on my lowest sprocket on the 39 ring. I'd settle for a compact though, if there is no such middle ground.

freehub

I don't think there is a problem going from a double to compact, the rear mech should be fine, the only adjustment you'd have to make is moving the mech down slightly.

You can change rings on chainsets but I don't know if a 34 would go on a chainset that was a double, something to do with something to do with the bolt positions I think. BCD is it?

blorg

Yes, Bolt Circle Diameter (BCD)- 130 for a standard double, 110 for a compact. This defines the smallest ring you can put on and you can't go below I think 38 on a standard 130, so you have to change the entire chainset. The only other thing you need to do as Will says is lower the front derailleur. You MIGHT also have to shorten the chain to cope with the smaller 34 ring.

52/34 would be too big a range for the front derailleur, 16T is the max range. This is the spec, in practice you MIGHT get it to work, I don't know. Shifting does get worse the bigger the range and is better on a 53/39 than a 50/34 (I have both, as well as triples.)

IIRC Contador and Astana used a 53/34 compact with 11-28 on the back (some even said 30) for the Angliru stage in last year's Vuelta but I think I also heard that once they shifted down into the small ring there would be no getting back up out of it- not a problem as it was a mountain top finish.



If you want the big gears best off getting a cassette with an 11T, as 50-11 is a much bigger gear then 52-12. You can get SRAM cassettes in 11-28 which gives you a big range.

As for rear derailleur, I have a short cage DA one and run between 53/39 11-23 and 50/34 12-27 and it all works fine. I have long cage on my bikes with triples.

Onan

Thanks for your help. Much apreciated.

kevsterjw

....

John.T

http://www.chainreactioncycles.com/Models.aspx?ModelID=31293
Try this one.

kevsterjw

...

John.T

Yes but you would also need the BB units. Also check your crank length. These are 175mm. Your current crankset is not Sora and I think has a sqare taper BB. It is 130mm BCD. A compact is 110mm. You could fit any compact square taper crank providing it uses the same BB length. This one may fit.
http://www.spacycles.co.uk/products.php?plid=m2b0s109p45

dov2711

Like many before me I would appreciate any advice from the mechanicaly minded amongst forum users.

I have got back on the bike over the last while and have had a great time. Trouble is that a mixture of pushing myself too hard and in the view of the Physio an insufficient range of gear choice has saw a return of knee and thigh problems dating back through my years of football.

So the question is the regular one of how do I widen my granny gears (thats really a sentance I didnt think I would ever consider discussing!!)

I have a Specialized allez 16 so wonder whats the simplest "quick fix" and what are the more exensive options (if my long promised tax rebate ever arrives)for the longer term as I would intend to hold on to the bike for winter use when I upgrade next year.

Bottom Bracket: With Crankset
Brake Levers: Shimano Sora STI, flight deck compatible
Cassette/Freewheel: Shimano HG-50, 9-speed, 12-25t
Chain: HG-73
Chainrings: 50 X 34t
Crankset: Shimano Sora
Front Brake: Shimano Sora
Front Derailleur: Shimano Sora
Front Hub: Forged aluminium, 32h, sealed ball bearings, QR
Gear Levers: Shimano Sora STI, flight deck compatible
Handlebar: Specialized Comp Ergo, 6061 alloy
Headset: Cage bearings integrated w/ headset, 20mm of spacers w/ top cap
Rear Brake: Shimano Sora
Rear Derailleur: Shimano Tiagra
Rear Hub: Forged aluminium, 32h, double sealed ball bearings, cassette, QR
Rims: Alex S500, aluminium, sleeve joint, CNC machined sidewalls

John.T

The cheapest and simplest option is the change the cassette to a 12/27. This will give lower gears on the biggest 2 sprockets without messing up the rest. It also takes you as low as you can get without some slightly non standard setups which would leave wider gaps between gears. The next option would be to go for a triple chainset. This would require a chainset, front and rear mechs and a new chain. If you did not also go for the 12/27 cassette you would end up with a lowest gear not much lower than you get with 34/27.
I would recommend getting the 12/27 cassette and making more use of the lower ratios to maintain a cadence in the region of 90 rpm most of the time. And don't push too hard. It will come in time. Overdoing things just sets you back. Be prepared to walk that hill if it means busting a gut to ride it.

jonesy5

New to this cycling lark, great fun and really enjoying it, but would appreciate a wee bit of advice please

I have a GT series 4 with a 50/34 compact and Sora 8 speed 12/25 cassette. I’m based in the Peak District & although wonderful cycling county, the hills are getting the better of me. I’ve been to my LBS and the advice that I’ve been given is that the cheapest/easiest option would be swapping the cassette for a Sora 8 speed 13/26 cassette. I’m considering it, but how much difference would that extra tooth make up say a 10-12% hill :?:

Jonesy :

John.T

Very little I'm afraid. If you are really struggling you may have to go for an MTB cassette and rear mech. You would also need a longer chain.

jonesy5

Cheers John
I did wonder.
I think I'll just stick with it for the time being, try and lose a few pounds & just get fitter (47 & 15 stone). I don't want to spend £100s of pounds changing a low end spec bike. Altough the hills are getting slightly easier, it's a slow process & pehaps i'm being impatient. It's anything around 10% that's getting me - but lots of good advive on the other theads.
With hindsight, I should have brougt a triple. I shall be more wise when I upgrade

rickhotrod

An 8 speed 12-25 Shimano cassette has 12,13,15,17,19,21,23,25 sprockets.

One way to get lower gears is to change the 23 and 25 sprockets to 24 and 28. The 24 and 28 sprocket can be taken from an 8 speed 11-32 cassette such as HG30, HG50, etc.

The largest sprockets on the HG30 and HG50 are held together with 3 rivets. Drill the heads off the rivets (located on the back of the largest sprocket) and the rivets should then push through to free all the sprockets.

A 34/28 is a low bottom gear. When you're fit, change the 24 and 28 sprockets back to the original 23 and 25!

STEFANOS4784

Yes i should think so Will check out the facebook thing later and give definate answer...

Avoneer

I have a Truvativ Touro 50/36 on the front and Shimano HG-50 12/25 on the back and struggle on a few hills here in Yorkshire.

Would simply changing the front 36 to a 34 make a noticeable difference without having to change anything else?

Thanks,

Pat...

John.T

The 34 would help. You can get a 33 on. See here.
http://www.spacycles.co.uk/products.php?plid=m2b0s149p433
Going to a 12/27 cassette will also help but that is as far as you can go without a lot of messing about.

rickhotrod

Avoneer wrote:

I have a Truvativ Touro 50/36 on the front and Shimano HG-50 12/25 on the back and struggle on a few hills here in Yorkshire.

Would simply changing the front 36 to a 34 make a noticeable difference without having to change anything else?

Thanks,

Pat...

As well as or instead of a change from 36 to 34, change the 12/25 to 12/26.

If it's 9 speed you can modify the 12/25 so that it becomes a 12/28. To do so, dump the 14 sprocket, and fit a 28 from an HG50 11/32.

soveda

Just to check, I have a tiagra short rear mech, can I keep that to go from a 50/34+12-15 to 50/34+12-27?
I know I may have to lengthen the chain but the 17% hills are a bit too much for me with a 34-25!

John.T

Yes you can, but as you say you need to check chain length. This is covered earlier on this thread. Riding in the Dales I would never consider a 12/25 against a 12/27.