Moving from Triathlon to Raiding the Pyrenees

BigTallJim

I bought my Cube Attempt compact a couple of years ago as a bike to use for my Triathlons. It has done a very good job !

Excitingly, or stupidly (I'm yet to decide), I've signed up to ride across the French Pyrenees. 709km and 11,000m of climbing over 5 days.

I think I need a lower gear. My first thoughts were to order a new cassette, maybe one which goes up to 30 (rather than the 11-28 on the bike).

I'm happy to have a go at replacing the cassette myself, but have two questions

1) What size cassette would people recommend
2) Do I need to replace the chain or the arm which changes the gears as well

I guess the other option is to change the front crank ! but I'm not sure which option is best.

Thanks

James

pilot_pete

It all depends!

I just rode the Pyrenees from west to east - 450 miles with 64,000' of climbing. It was my first time there and I had a compact crank (50,34) and 12-25 cassette. Anything steeper than 10% was a bit of a grind to be honest. I am a reasonable climber for my 82kg bulk, more suited to power climbs rather than really short steep stuff, and we climbed all the big ones - Marie Blanque, Aubisque, Tourmalet, D'Aspin, etc etc. with hind sight I would have liked a 27 on the rear to enable me to keep spinning on the really steep bits.

So it depends how much climbing you have done, how strong you are, etc etc. if you can fit a bigger cassette it will certainly help, see the manufacturers website technical documents for cassette options and derailleur cage compatibility.

Main thing is to enjoy it, I thought the whole experience was brilliant, even if I had to grind a few Kms out!

PP

BigTallJim

Thanks for this, I'm not a bad climber on UK hills, but suspect the Pyrenees will be a rude awakening. I'm quite heavy (95 kg) so may need all the help I can get.

oldwelshman

If your 95kg I would say a 13 to 27 on the back which will give you more even gears for climbing and stick a compact on the front 50/34. If you cant get upthose climbs on 34 27 you will be going so low may as well walk

MichaelW

When I lived in hilly Hastings, I used by 28/28 every day. The idea that its better to walk rather than use a low gear is just incorrect. Whether you need a 27"/1:1 ratio depends on your power/weight/steepness. I found that the Pyrenees were very steep only in a few short stretches, mostly it was about 10-12%.

smidsy

If you are fit and do triathalons I would suggest the 28 you already have on the rear is sufficient - especially if you have a compact on the front.

Bobbinogs

...and don't forget to buy some jerseys with short sleeves rather than no sleeves

rdt

Pilot Pete wrote:

It all depends!

I just rode the Pyrenees from west to east - 450 miles with 64,000' of climbing. It was my first time there and I had a compact crank (50,34) and 12-25 cassette. Anything steeper than 10% was a bit of a grind to be honest. I am a reasonable climber for my 82kg bulk, more suited to power climbs rather than really short steep stuff, and we climbed all the big ones - Marie Blanque, Aubisque, Tourmalet, D'Aspin, etc etc. with hind sight I would have liked a 27 on the rear to enable me to keep spinning on the really steep bits.

So it depends how much climbing you have done, how strong you are, etc etc. if you can fit a bigger cassette it will certainly help, see the manufacturers website technical documents for cassette options and derailleur cage compatibility.

Main thing is to enjoy it, I thought the whole experience was brilliant, even if I had to grind a few Kms out!

PP

+1

It depends on a bunch of things: fitness & fatigue, weight and climbing style. I'm not a disaster on the hills, don't carry excess weight, but I like to spin.

Previously in the Alps and Pyrenees I've used 34/27 and been fine, while a mate with a different style used bigger gears for the same speed. With the lesser gradients compared to here (Peak District) I remember thinking I might not use the 27 sprocket, but as Pete wrote, grinding away for hour after hour without break takes its toll in a manner that UK climbs don't really prepare you for - particularly if you throw in some proper heat. Next trip I think I'll go for a lower gear still (11-32 SRAM cassette), as I reckon I'll be quicker up the steepest stuff due to being able to spin ~15 rpm faster for the same speed, if need be. I've a long cage rear mech so this cassette should work OK (I believe).

If riding in mountains where you're either grinding up hill or tanking down the other side, there's little downside to swapping an intermediate (flat-riding) sprocket for a super-granny sprocket IMO, even if you never end up using it.

Some example calculations from http://www.machars.net/bikecalc.htm :-

My mate uses 39/25: @7.9mph, he's pedalling at 65rpm
Me using 34/27: @7.9mph, I'm pedalling at 80rpm
Me using 34/32: @7.9mph, I'm pedalling at 95rpm

That offers me a lot of flexibility on long steep climbs (esp at the end of long hard days!). YMMV.

ugo.santalucia

I have done the Raid Pyrenees too a couple of years back... as you don't do the Marie Blanque, the only climb where you do need really small gears is the Portet d'Aspet... it's 4Km at 10%... I did it in 34x28, if you have a compact you can do it, otherwise just grind on the gears, it's the last climb of the day anywway.
The big ones, like Aubisque and Tourmalet aren't particularly steep, same for Aspin and Peyresourde.

Wouldn't bother with a 30 teeth cassette that might require a longer cage derailleur. Maybe a compact chainset if you don't have one... but it's perfectly doable with a 53x39

rdt

ugo.santalucia wrote:

I have done the Raid Pyrenees too a couple of years back... as you don't do the Marie Blanque...

Ah, it was the west side of the Marie Blanque I had in mind - tough climb (though not too long)!

ugo.santalucia

rdt wrote:

ugo.santalucia wrote:

I have done the Raid Pyrenees too a couple of years back... as you don't do the Marie Blanque...

Ah, it was the west side of the Marie Blanque I had in mind - tough climb (though not too long)!

Yes, but it's not part of the Raid Pyrenean, at least not in the 100 hours time limit version... I think it is part of the Randonnee type one, longer, hillier but without time limit.