50/34 or 52/36

fat daddy

Ahhh I am so confused, I am rebuilding an s-works roubaix

Currently have on there all ultegra equipment including a 12t-25t cassette ... What crankset should I pair with this ?

6700 or 6750 .... Either 52/36 or 50/34

Is the compact going to better for me as a relative newbie or is there an advantage in the more common bigger rings ?

Thanks

mrb123

I predict this will run to at least 10 pages...

fat daddy

ah ... that is a more helpful answer than you think ..... it must not make that much of a difference and whole depends on my preference

if there was a correct answer it would only spread across 3 posts

mrb123

fat daddy wrote:

ah ... that is a more helpful answer than you think ..... it must not make that much of a difference and whole depends on my preference

if there was a correct answer it would only spread across 3 posts

Is the right answer!

fat daddy

ok, the cheapest and the lightest then ... how much does a tooth weigh

mrb123

viewtopic.php?f=40042&t=13066843

fenix

Go 50/34 if you do hills.

bendertherobot

I did the Bwlch yesterday on my 11-28 52/36 and it was fine. Indeed it's been fine on all Welsh hills.

For the Marmotte next year I may swap it out to a compact.

fat daddy

MrB123 wrote:

http://www.bikeradar.com/forums/viewtopic.php?f=40042&t=13066843

Ahhh, thankyou, I did "attempt to search yesterday, but for some reason there is no search function when I use iphone .... but I did expect this to have already been covered.

Its a useful thread, especially the link to the gear-calculator that shows the difference is a mere 1mph at each end if I keep the cassette the same

I compared it to my commuter hybrid this morning that I have "discovered" is also using a 50/34 but with a crazy 11-32 cassette

in 50 - 11 I do use that gear, but no where near spinning out, not even close, I just cruise in it 24mph .. but find I change down at the slightest of head wind or elevation

however I do use the 32t on the 34 for one of the hills when tired and lugging fully loaded panniers ...... so thinking I'll stick with the 34t as a 36 - 25 could see me struggle ???

Cheers for the info guys and gals, sorry for bringing this one up again

webboo

I finally managed to spin out in my 50 x 12 yesterday 43.5 mph Oooh look at me 8)
Although I will changing my chainset to 52 x 36 I would hate to be out of fashion what ever the cost.

lesfirth

If someone secretly changed your chainrings with some 2 teeth more or less ,how long would it take you to notice that something was different? I think it would be when I cleaned my bike and saw the numbers on the rings.

drlodge

Fenix wrote:

Go 50/34 if you do hills.

This.

What's the lowest gear you'll need? Then work out, given whatever cassette you're using, whether you will need a 34T rather than a 36T. I would suggest you will.

FYI I run 34/50 with a 12-29 cassette, I do have a 36/52 on another bike with the same cassette but struggle on steep hills. 34/50 all the way.

My bottom gear is too low...said no man ever.

keef66

Yep, down to personal preference, how much power you produce, the type of terrain you ride, whether you're a spinner or a grinder etc etc.

When I built up my summer bike I was trying to do it on a shoestring budget and bought a 9 speed Tiagra groupset off the classifieds on here. Chainset was a standard 53/39, cassette a 12-27. Thought I'd get used to it, but now in my late 50s I found I was using the big chainring pretty infrequently. I favour a cadence of around 90, so tended to stay in the 39 all the time. I'd never in a million years come close to spinning out in 53X12!

Swapped it out for a CX 46/36 chainset and find I now get similar use from both chainrings.

If you have proper hills to climb I'd say go for 50/34, and also get a cassette with some bigger sprockets...

bernithebiker

fat daddy wrote:

Is the compact going to better for me as a relative newbie or is there an advantage in the more common bigger rings ?

Thanks

As a 'relative newbie' it has to be 50/34 all the way. And bigger rings are not 'more common', 50/34 is widespread and very popular for good reason.

On the Etape du Tour recently I used a 50/36 with 11-28 and regretted not having the 34 on the Joux Plane, a very tough climb. I passed some very pro looking riders on 39's who were all at sea. One guy even wobbled down to 5km/h, then collapsed sideways. These are racers who will be doing over 40km/h in weekend races, but have no idea how to tackle big hills. And the silly thing is that their 53/12's will have gained them nothing on the downhills.....

fat daddy

Thanks for all the advice.

I opted for 50.34 in the end, partly driven by the fact that I am a road newbie, partly driven by the realisation that one of the hills on my way home, if I am too weak and carrying a few kg's of shopping I end up in 34t on the front and 32t on the back .... So I think that even on weekend rides on this bike I might want for the favourable 34 - /25t ratio. But mostly because I sourced a very cheap fc r700 50:34 from a shop with old stock.

Despite the "older" ultegra components on her, the bike weighs in at dead on 8kg

I think I can live with that until I decide what gearing I need and hopefully I can pick up a old Dura ace group set and get the bike below 7.5kg

imposter2.0

Don't over-estimate the effect that saving 500g will have...

drlodge

Imposter wrote:

Don't over-estimate the effect that saving 500g will have...

Yeh, just half fill one large bidon for maximum effect.

keef66

I don't obsess about the weight of the bike. I managed to shave 18 pounds off the combined weight of bike and rider

fat daddy

but I like obsessing ... And besides which I have lost 10kg this year ... It's only fair that bike suffers as well and goes on a diet ... Err, not that I have actually ridden it yet, just built it.

alan_sherman

I'd guess that the 50x34 would be a good choice, and buy a 36 ring to make a 50x36. (or a 38 actually)

You could get the 52x36 and buy a 34 ring for climbing but the jump is theoretically to big for the front changer and even if it works it wouldn't be nice jump in range from inner to out ring. So you might well need to buy a 50 anyway to use the 34.

So a 50x34 is a cheaper option. When you change cassette get one that starts at 11 to get a higher top gear if you need to.