What chainring and cassette for hilly races

viperlogic

Hi all, had a duathlon race over the weekend in which the route had to be changed last minute and meant there were lots of hills! My tri bike has 53x39T upfront and 12-28 cassette in the rear and I was struggling on some of the climbs. I'm more a high cadence rider than pure tree trunk leg power!

What would be the best route to take, bar leg strength training, as have another hilly duathlon coming up in 2 weeks...
- change the rear cassette to a 12x30 thou that will only change the ratio from 1.4 to 1.3
or
- change the granny ring up front from a 39T to a 34T to bring the ratio down from 1.4 to 1.2

Any help most welcome

07Lapierre

Don't think you can change the 39 to a 34 chainring, so your only option is a new cassette on the back. As you already have a 28T sprocket, I'd say your options are limited to the 30T

Ryath

If it's hilly enough that you can't climb on 39*28 is there much point to using a TT bike for the race better of using a road bike lighter and better for climbing.

You can't change the front chainring without changing the crankset. 38 is the smallest inner ring on a standard.

Depending on your rear mech you probably can put on a 12-30 cassete bear in mind the bigger the cassete the more gaps you will have in your ratios you may find it hard to be in a gear with a cadence your comfortable at.

viperlogic

Ryath wrote: »

If it's hilly enough that you can't climb on 39*28 is there much point to using a TT bike for the race better of using a road bike lighter and better for climbing.

You can't change the front chainring without changing the crankset. 38 is the smallest inner ring on a standard.

Depending on your rear mech you probably can put on a 12-30 cassete bear in mind the bigger the cassete the more gaps you will have in your ratios you may find it hard to be in a gear with a cadence your comfortable at.

Unfortunately I sold my road bike to pay for the TT bike!

I will have a closer look at my crank/chainring tonight but I'm sure its a two piece chainring

Ryath

The cranks and rings are separate. What make is your crankset?
Most cranks are either compact 110bcd usually 34/50 or standard 130bcd 39/53.
Shimano have a new 110bcd 4 bolt standard that can use any of size of their chain rings. If you have newest 11 speed ultegra or durace you can change your chainrings for whatever you like

viperlogic

Crank is Shimano FC-R550. Derailleurs and shifters are Ultegra 6700

Chips Lovell

If it's a short cage rear mech, the biggest sprocket you'll be able to use is 28. If it's a long cage, you'd be able to go up to 30.

Brian?

viperlogic wrote: »

Crank is Shimano FC-R550. Derailleurs and shifters are Ultegra 6700

28 is the biggest you can go on the back without changing derailleur and you can't put a 34 on the front.

Hill repeats it is .

07Lapierre

New (Road) bike it is!

viperlogic

Vladimir Kurtains wrote: »

If it's a short cage rear mech, the biggest sprocket you'll be able to use is 28. If it's a long cage, you'd be able to go up to 30.

I have a short cage RD-6700SS Rather than complete overhaul looks like hill repeats it is!

morana

where is the race? The Alps?

Seriously 39x28 should be fine for anything in this country

jinkypolly

Brian? wrote: »

28 is the biggest you can go on the back without changing derailleur and you can't put a 34 on the front.

Hill repeats it is .

That's not what plenty of posters on the internet are saying, 30 on the back seems doable.

Brian?

jinkypolly wrote: »

That's not what plenty of posters on the internet are saying, 30 on the back seems doable.

It is doable. But it's a Gunther. It's no good for your chain and will shift horribly.

As morana says, a 39x28 should be grand for most hills in Ireland.

viperlogic

morana wrote: »

where is the race? The Alps?

Seriously 39x28 should be fine for anything in this country

Next race is Bantry in Cork.

My legs were fairly shot last weekend as did a fast 20 mile run two days before hand, hence struggled on the hills and would of liked an easier gear.

Ryath

Don't mean this personally but what sort of weight are you op?
If your lightish and in good shape there is nothing in Ireland you can't climb on a 39*25

.

Ryath

Sorry never though about the running bit of it. I know holding a high cadence is better for running of the bike. You may be better changing your cranks there are good deals online if you look around. Probably under €80 not much more than the cost of new chain rings any way.

Guess don't do hard 20 mile runs two days before a race either.

viperlogic

Ryath wrote: »

Don't mean this personally but what sort of weight are you op?
If your lightish and in good shape there is nothing in Ireland you can't climb on a 39*25

.

82KG. My strength and passion is running but like to do the odd bit of cycling eg duathlons and sportives. My old roadie had a triple so was simple flying up steep hills. It's really just a case of hill training as others have said. Spent the winter on the turbo, yes, I'm soft out!

Ryath

https://www.planetx.co.uk/i/q/CSFSAGOS13/fsa-gossamer-chainset
€79 delivered

Just be aware what bottom bracket you have

joxerjohn

You may get away with a 30t sproket on the back with your current RD, might be worth a try. The shimano spec on RD will say 27 or 28t max but there is a bit of wiggle room.

You could get a Tiagra 12-30 for about €25 or so and if it did not suit I am sure you could sell it on. As you have already pointed out however, it wil not made a huge difference ratio wise.

Work on your pedalling technique and get in some more hill repeats. You should also try and reserve your 28t as a last resort to be used only on the steepest of ramps. It is always nice to know you have a little extra if needed.

bambergbike

Ryath wrote: »

Don't mean this personally but what sort of weight are you op?

I was just wondering whether anybody on here could say anything precise about how weight loss (assuming one has surplus weight to lose in the first place) correlates to changing gearing needs. Back in February I was quietly pleased to be getting up one-in-five climbs that early in the season without having to get out of the saddle and without my heart rate going through the roof. I started thinking about evil sportives.

Then I bought a lighter bike on Saturday. Hills have suddenly got hard. Turns out Old Bike has 32 teeth on the largest sprocket at the back and New Bike has 26 (or maybe 25?), so I've lost six somewhere along the way. I was passing my LBS earlier and went in to get an idea of their suggestions for changes to the gearing. I was told that going from 26 to 28 on the back would give me the equivalent of 2 more gears, and that the derailleur would probably also let me go to 30 if I wanted to. I'm pretty sure I don't need 32 even though I was using 32 up to now; New Bike is smaller and lighter and Old Bike is the bike equivalent of the Incredible Hulk, so the choice is probably between 28 and 30.

What I'm trying to guess at now is how many kg (or what percentage of my weight) I would have to shed to climb as comfortably on New Bike as on Old Bike if:
1. I change nothing about the bike, or
2. if I get a new cassette with a 28 cog and a new chain?

I am overweight, but I'm not really planning to take off more than 4 kg before my evil sportives - how much difference would that make?

I'm slightly mortified to need even easier gearing than what the triple I have (with a 30 on the front?) gives me, but at the same time I know that it was great to have it last summer when I was doing the odd tour across the mountains with laden panniers in blazing sunshine. So the question is really just how much to change and when. Is there any point in doing a six week block of hill training with the "wrong" gears before switching over?

NeedMoreGears

I am guessing you are running out of strength with the 26 as compared to the 32. The 26 is about 20% harder to push in terms of pure leverage (6/32) so you'd need to lose 20% of your weight (plus the bike) for it to feel as easy, assuming you could maintain your strength and power output. Of course you'd fly up the hills quicker in that case. You might be better putting on a 30 and doing a few hill repeats until you can build up a bit more strength.

FWIW there are plenty of hills I'd have a lot of trouble with using 39/25 and my old legs. I'm 72kg (5 foot 6 so not exactly scrawny but not too heavy either) and in reasonable shape. 34/28 or even 34/30 are pretty handy when it gets to 7 or 8 percent especially if you have full panniers.

Max_Charger

viperlogic wrote: »

Next race is Bantry in Cork.

Haven't done the Bantry Duathlon itself but know the bike route extremely well. There is no major hills to worry about except maybe the initial climb out of Bantry town by the cemetery, but the trick with that one is to take it easy at the short steep bit between the cemetery and the Westlodge hotel and have the energy then to hammer it when it gets less steep between the hotel and the opel garage. You should be fine with a 39/28 for that event imo.

nooneuno

Ryath wrote: »

Don't mean this personally but what sort of weight are you op?
If your lightish and in good shape there is nothing in Ireland you can't climb on a 39*25

.

Mamore Gap should test that theory. :-)

Wishbone Ash

nooneuno wrote: »

Mamore Gap should test that theory. :-)

+1
Had to do the walk of shame with a 34/27.

I managed Kilmashogue Lane last week on a 34/28 but it was agonising. I was down to 6km/h on the +20% bits.

Alek

Whats the max real gradient on the Kilmashogue, including the offroad bit? My Garmin recorded 16%, but it felt much more in places...

(done it first time last week, overestimated myself and had to stop couple of times to catch some breath... :cool: )

Hmmzis

Alek wrote: »

Whats the max real gradient on the Kilmashogue, including the offroad bit? My Garmin recorded 16%, but it felt much more in places...

(done it first time last week, overestimated myself and had to stop couple of times to catch some breath... :cool: )

I think in the Strava segment details of the last ramp it shows places at 22% with an average of 16.4% for last couple hundred meters. A 39x25 is tough going there but certainly doable. Top section of Kippure mast hill feels a lot worse after Sally gap and Stocking lane in the legs.

Alek

Kippure wasn't much harder for me to be honest, coming from Eniskerry - but maybe because the goal was sooo cloose :-) Or maybe it wasn't my best day for Kilmashogue... need to try again :-)

(39/25? Crazy in both cases.)

Chips Lovell

OP was on gearing for hilly races. And the only race I know of that's gone over the Gap of Mamore is the Rás. And if you're doing the Rás, you're probably using 39/25. So in relation to cycle racing, it's a fair enough comment.

Having said that, OP is doing duathlons, which maybe is a different kettle of fish.

Wishbone Ash

Alek wrote: »

Whats the max real gradient on the Kilmashogue, including the offroad bit? My Garmin recorded 16%, but it felt much more in places...

(done it first time last week, overestimated myself and had to stop couple of times to catch some breath... :cool: )

My Garmin showed 23% at one point (on the paved road). The urge to stop was overwhelming but I soldiered on.

Welshkev

Ryath wrote: »

The cranks and rings are separate. What make is your crankset?
Most cranks are either compact 110bcd usually 34/50 or standard 130bcd 39/53.
Shimano have a new 110bcd 4 bolt standard that can use any of size of their chain rings. If you have newest 11 speed ultegra or durace you can change your chainrings for whatever you like

Sorry to hijack, but just on this - I have the new Ultegra 6800 11 speed, but it's a compact and would like to change (at least the front) to a standard - 53 - is it litterally as easy as buying a new 53 front ring and swapping them out?

maloner

I have a 50/34 and an 11/28 setup. I don't think I've been in the 34-28 during a race at any stage, but I'd cross chain from the 50 to the 28 from time to time. The ratio is a it jumpy but staying in the big ring can be handy. I wouldn't be in that gear for too long though as I've more choice in the small ring. The gears don't have as many gaps.