Considering lower gears

185nick

Hi, I'm new to road riding and bought myself a Pinnacle Lagerra 1.0 a few weeks ago:

http://www.evanscycles.com/products/pin ... gn=froogle

I love the bike and am hooked already. However, not being the fittest person at the moment and living in a hilly area I've been considering changes to my drive chain to get some lower gears. I'm not sure of the best way to do this so was hoping you guys could give me some advice please? At the moment by bike has an FSA Omega compact mega exo chainset with 34/50 chain rings and Shimano 105 11-25T 10 speed cassette.

I've thought of two choices, the first is to change the cassette but sticking with a 105 10spd cassette means that I can only get a 12-25T or 12-27T. I'm not sure how advantageous the 2 extra teeth will be and also will I have to change my chain to get some extra length? The chain is new so shouldn't have any issues caused by wear.

My second choice is to change the chainset from compact to triple, I can get an FSA Omega Triple Mega Exo chainset with 30/39/50T. Being the same make and model as the chainset already on there will I get away with not changing the BB? Will I have to change my front mech? My front shifter is 3 spd so won't need to change this.

I read on this forum a couple of weeks ago about an adaptor to change a double chainset to triple:

http://www.spacycles.co.uk/products.php ... 0s149p1141

This would be the cheapest option if I don't have to make too many changes. Do you think I could get a 39T adaptor then stick a 30T inner chainring to it? Again would I need to change my front mech.

What option do you think is best please? Any help would be fantastic.

Many Thanks
Nick

duncanw

I think the easiest and cheapest method will be to replace your cassette.

You might well be able to fit a mountain bike cassette but am not sure about the compatibility and whether you might need adapters etc, you might also have to drop down to 9 gears.

FCE2007

I've just gone 12-27 from 11-25 and the Ultegra derailleur/chain is fine.
The extra 2 teeth deffo made a difference. I also gained 50/16 in the ratio which I didn't have before. 34/25 is a good gear but it's nice to have another lower for 'emergencies'

STEFANOS4784

Check the sticky at the top of the board should tell you all you need to know

185nick

Thanks alot guys. Have just spotted the sticky a moment ago and am currently reading though it, but if anybody has any specific advice then that would be great.

FCE2007-Thanks for that I wasn't sure how much difference 2 teeth would make so it's great to hear from someone who has made the change.

185nick

I have read the sticky and have decide against getting a triple chainset. Still can't decide between just a change of cassette 12-27T or the adaptor to change my compact to a triple. According to a post in the sticky I may get away with not changing the front mech as long as I don't run small/small which, coming from MTBing, I never do anyway, but do you think I would have to change my rear mech to a long cage version?

duncanw

Looks like your rear mech can go up to a 29 rear sprocket.

http://www.westernbikeworks.com/product ... sp?p=SH5RD

John.T

No it does not. It goes to 27 teeth max. The 29 refers to the max teeth difference between big/big and small/small.

pete600

had a 11-25 on my c2c had the same problem the hills where i live where killing me. Just by chance when i was out riding called in to the LBC got the guy to change to a 27. It made a difference on the way home had to go over 2 hills 18% and 13% got over them a lot easier.

morxy

I'm running a SRAM OG-1070 11-28T cassette on a Dura Ace short cage rear derailleur. Many people say the max is 27t. Maybe that's what Shimano's product spec says. But in reality you can run 28t on short cage rear mechs - and not just Dura Ace. I'm also running 11-28t on a Sora short cage mech as well.

Specialized sell some of their bikes with 11-28t cassettes on short cage mechs. You should be fine

185nick

Thanks a lot guys evryone's been a great help. Have decided I'm going to go for changing the cassette.

John.T

You can get away with a 28 on Shimano short mechs but on some frames you can not adjust the 'B' screw enough for the jockey to clear the big sprocket. On others it works. A 29 is really pushing it but if you know what you are doing it may work. I would never recommend it to a novice.
Nick is already considering 50/34 with 12/27 which is 31 teeth. This is quite safe as long as you get the chain length right but much more and you would either get a slack chain on the 34 with the smaller sprockets or a mech in your back wheel if you hit big/big by mistake. With 50/34 and 12/27 you can if you so wish safely use all gears.
The only Specialized models I could find with 11/28 on were SRAM equiped.