Teach me oh wise ones

[MuffDaddy]

Morning all,

This weekend I completed the Blenheim Triathlon, completed/finished would just about cover my efforts. I nailed the swim, I was never going to be great at the run (lack of training), but I was a little surprised at the cycle.

I have this:
http://www.evanscycles.com/products/globe/vienna-1...

I found on the downhill sections the the gearing didn't allow me to pedal (I'm sure there is a term for this), on the uphill I also didn't have quite the range of gears I wanted. Until I do a few more tri's I don't want to go to the expense of a proper racing bike, so what would the collective do to modify/improve the bike I have.

Before anyone suggests improve the rider I have now started to train properly for the next tri.

Thanks

[missing the VR6]

I'm no expert but if the gear ratio's didn't suit that'd be my first port of call to change. I couldn't even begin to offer advice on what to go for as I'm MTBer and haven't a clue about road/hybrid bikes. I suppose your other option would be to get some carbon on there to lighten it up to ease the climbs.

[Kermit power]

I can understand you running out of gearing on the downhill. Your fastest gear is 48 teeth on the front and 13 on the rear, whereas even a compact chainset would normally give you 50x12.

What the above means is that assuming you're turning the pedals at 90rpm, with your current bike, you'll run out of gearing at 25.98mph, whereas on a 50x12 you'll get to 29.36mph before you run out.

I'm rather more surprised you were running out of gears going uphill, assuming by this you mean you would've liked an easier gear? Your easiest gear currently is a 28x34. You can get cassettes with up to 36 teeth, but the difference would be pretty marginal. Bear in mind that there's only so slow you can ride a bike before you fall off! Assuming you want to maintain a minimum of 3mph, then you'd only need to turn your current 28x34 at 47rpm, as opposed to an almost imperceptibly different 49rpm for the 28x36.

If you're struggling to get up hills with your current gearing, either there's something very, very wrong with your power to weight ratio (and this coming from an 18 stone, amply insulated rider), or there's something wrong with your bike. Most obvious first question - have you looked down to make sure that it's engaging the smallest front cog? If the front mech isn't properly set up, it could be that you're only dropping down to the middle ring. Frankly, even that should provide enough hill gearing for someone fit enough to contemplate undertaking a triathlon. I'm a country mile away from that sort of fitness level, but my first gear (34x26) is 17% harder to push than the easiest gear on your middle chainring (38x34), and is enough to get me up climbs of around a 9% gradient before I need to get out of the saddle.

My mountain bike has similar gearing to your bike, and on that the thing that stops me pedaling up steep hills is invariably my centre of gravity tipping me off the back of the bike, not me running out of gearing.

[okgo]

Agree with Kermit. That 'megarange' gear should get you up anything. My gf got up ditching without getting off and she doesn't ride bikes.

Everything else said above is correct.

[MuffDaddy]

Sorry, I meant the shift between 1st and 2nd is a big difference, so when it calls for 1st I lost momentum.

So first of all maybe I look at changing the higher gears to increase top speed and work from there. I'm assuming this isn't rocket science to make those changes?

[anonymous-user]

MuffDaddy said:

Sorry, I meant the shift between 1st and 2nd is a big difference, so when it calls for 1st I lost momentum.

So first of all maybe I look at changing the higher gears to increase top speed and work from there. I'm assuming this isn't rocket science to make those changes?

i wouldnt bother changing chainsets and casettes, you are making a bike wholly unsuitable for the event only marginally more suitable by doing so but there are still lots of other things that will inhibit your performance, notably the geometry of your bike and the subsequuent body position, the tyre contact on the road and the drag associated. Hybrids are too upright and you will take a huge amount of pressure on your chest which will be slowing you down comapred to being tucked down on a road bike.

i appreciate its easy for us to spend your money but a good road bike need only set you back £350-£500 and will make the world of difference. A compact chainset and casette will be the best part of £75 for a reasonable standard.

[AndrewEH1]

While that bike is fine for general use if you want to do a lot of triathlons (that are road cycling based) you might want to get a more suitable road bike, or time trial/triathlon bike, rather than a hybrid.

When you are on downhills and in your highest gear and you can't pedal, freewheeling, it simple means that you are going too fast. If you want to go faster you'll need to increase you gear range. That will involve changing both the chainrings and cassette. (Front and back gears!)

I can't give any advice on the gear ratios to go for as I'm not a roadie.

What was the issue with the uphill? Not a small enough gear so you could keep pedalling?

[Roman]

Just fit an 11-28 cassette (and new chain) for a higher top gear and closer ratios, no need to replace your chainset:
http://www.ebay.co.uk/itm/SHIMANO-7-SPEED-HG-CASSE...