Just tried my new b...
 

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[Closed] Just tried my new bike..advice required on gearing please

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So I just picked up my new Caad X tiagra, 2017 model, which on bike to work will cost me a grand total of £360 quid..

First issue with it, its really heavy, 10.6kg (with pedals) which is actually heavier than my full sus xc bike with dropper post! New wheels on way however so not a massive issue.

But...it also comes with a ridiculous gear combo, 46/36 on the front, 11/28 on the back. Probably useful for CX racing, but for me pretty useless for the purposes that I bought it, winter training, adventure rides, and maybe even some touring.

So anyway, I'm now faced with a couple of options, and usually I'd just swap out the chainset of a 50/34 and stick a 32 cog on the back, which would mirror my road set up. Few issues however..

Firstly the chainset is BB30, so a quick swap will i assume mean adapters and more expense. I can deal with a 46 top end so I could just swap the 36t ring for something smaller..but wait a mo, it says the BCD is 120/90?????

As for the cassette, it looks like I have the short cage (ss) version that only handles the 28tooth max . Further confusion from the shimano website however as the longer cage verion appears to have a serial number RD4700 ss, mine is only a RD4700. Very confused.

So anyhow, what are my optons, bearing in mind this was only bought as it was cheap as chips, and I dont really want to reaplace the entire drive train.


 
Posted : 05/08/2017 3:34 pm
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Perhaps look on the classifieds for someone with a suitable chainset to swap to; those are weird.


 
Posted : 05/08/2017 4:55 pm
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I did something similar.. got a Merida CX500 to use primarily as a winter bike, switched the CX chainset for a tiagra 50/34 (bike shop was nice enough to switch out the chainset at no cost)
I have run an 11-32 cassette on a couple of bikes with the short cage mech, Shimano say it won't work but I haven't had an issue. It does depend a little on dropout geometry and gear hanger but I'd say it's more likely to work than not.
A mate I ride with has the same bike as me that he got on RTW scheme and he kept the CX chainset and doesn't have an issue with the gearing so it might work out better than you think..


 
Posted : 05/08/2017 5:07 pm
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Something to keep in mind is that tiagra 4700 has a unique pull ratio so if you want a mech that isn't 4700 you will need new sti's as well.


 
Posted : 05/08/2017 5:09 pm
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So you bought a new bike and didn't spot that it had the wrong gears for what you wanted it for?


 
Posted : 05/08/2017 5:12 pm
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MoreCashThanDash - Member
So you bought a new bike and didn't spot that it had the wrong gears for what you wanted it for?
TBH that was my first thought on reading the OP too.

And now you want to start heavily modifying a bike that's not even yours.


 
Posted : 05/08/2017 5:24 pm
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10.6kg for £360? Sounds like a bargain bike to me... why change things? Just ride it into the ground for a year.

Gears sound fine to me - 34/28 is as low as I'd want to go in the uk, and ok it's lacking up top but again for £360..

I'd ride it and see before spending the same again on the gears.


 
Posted : 05/08/2017 5:31 pm
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Man buys CX bike & is concerned it has CX gearing, if you wanted a touring adventure bike maybe something like a crossrip would have been better or a touring bike?


 
Posted : 05/08/2017 5:37 pm
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So you bought a new bike and didn't spot that it had the wrong gears for what you wanted it for?

No, I bought it as it was dirt cheap and had always intended to swap out the front or rear ratios..turns out I hadn't bargained on the weird BCD which appears to limit my chain ring options to pretty much zero..

And now you want to start heavily modifying a bike that's not even yours.

Ah I was wondering what pedant would call this out. I'm not sure that changing the wheels and gear ratios counts as heavily modifying, and as you know fine well the bike may not be technically mine for first 12 months, but you know fine well it will not at any point have to be returned.

thanks for your input though guys, helpful as always!


 
Posted : 05/08/2017 5:38 pm
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You may be better swapping the whole groupset, as 4700 is unique and theoretically won't work with anything else. Not sure whether you might get it working with other groupset bits with some fettling, possibly.


 
Posted : 05/08/2017 6:19 pm
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As above I'd probably buy a group set from merlin or something and sell your bits as new to recoup amounts


 
Posted : 05/08/2017 6:48 pm
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10.6kg for £360? Sounds like a bargain bike to me... why change things? Just ride it into the ground for a year.

Gears sound fine to me - 34/28 is as low as I'd want to go in the uk, and ok it's lacking up top but again for £360..

I'd ride it and see before spending the same again on the gears.

. Except that he doesn't have 34/28 low gear .


 
Posted : 05/08/2017 6:56 pm
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Something to keep in mind is that tiagra 4700 has a unique pull ratio so if you want a mech that isn't 4700 you will need new sti's as well.

That's not even slightly correct.


 
Posted : 05/08/2017 7:02 pm
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Don't think I've ever heard anyone call a sub 11kg bike heavy before.
You are Tyrion Lanister and I claim my £5.


 
Posted : 05/08/2017 7:21 pm
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New longer cage 4700 mech and 34 tooth cassette bought for 45 quid which has solved the issue and gives me the same low end for climbing.

Yeah for 360 quid it's the bargain of the century, and I always knew it was not going to be light out the box. Wheels weight 2.3kg and tyres 500g each. Having some new ones built up from parts I have which will knock off half a kg, and planning to buy some new gravel tyres so it should come in at under 10kg once done, and should make it alot more spritely.

I have a spare tiagra chainset but the bike has bb30. Given how quickly I expect the BB to seize I will consider upgrading at that point.. Any idea what the cheapest way to convert is?


 
Posted : 05/08/2017 7:36 pm
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Several adaptors available to allow you to run hollowtech 2 in a BB30 frame.
For example:
[url= http://www.chainreactioncycles.com/fsa-bb30-threaded-adapter-b3119-/rp-prod129935 ]http://www.chainreactioncycles.com/fsa-bb30-threaded-adapter-b3119-/rp-prod129935[/url]


 
Posted : 05/08/2017 8:02 pm
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That's not even slightly correct

Are you sure? Everything I've read about 4700 says it's essentially a stand alone 'set and won't work with older 10 speed stuff, nor (obviously) 11 speed.


 
Posted : 05/08/2017 8:13 pm
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Just swap the casette for an 11-23. That's what I run with a 38T narrow wide. The larger ring on yours will give a higher top gear so you will be fine.


 
Posted : 06/08/2017 12:20 am
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Are you sure? Everything I've read about 4700 says it's essentially a stand alone 'set and won't work with older 10 speed stuff, nor (obviously) 11 speed.

It works with all of the shimano 11spd derailleurs


 
Posted : 06/08/2017 6:56 am
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You should be able to change the outer ring to a 50, you should be able to change the inner ring too if necessary, rather than replace the whole chainset.

You could also try finding a 12-30 cassette which the mech should accommodate...

But like half the other posters I have to question the logic of buying a CX bike when what you really wanted was a road bike, and then changing it to be more road bike like.

Try keeping it as it is and give it a good go before changing half the drivetrain...


 
Posted : 06/08/2017 7:40 am
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I'm just glad a manufacturer is putting proper size gearing on cx bikes, good work Cannondale.


 
Posted : 06/08/2017 8:11 am
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Are you sure? Everything I've read about 4700 says it's essentially a stand alone 'set and won't work with older 10 speed stuff, nor (obviously) 11 speed.

It works with all of the shimano 11spd derailleurs

but it won't work with the old 9speed mtb rear mechs and the largest rear cog the tiagra mech will take is 34 - for my gravel tourer want to run a 36 on the back and have a set of 4700 STI's still in box to return as realised after I'd bought them the pull ratio is unique for 10speed - pity as all the reviews say are great - looks more like leapfrog update rather than trickledown


 
Posted : 06/08/2017 11:07 am
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duplicate


 
Posted : 06/08/2017 11:11 am
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Fir all those that keep saying you bought the wrong bike..

I don't want a road bike.. I have one

I started a thread on here asking if the caad x was suitable for my requirements.. Everyone said it was ideal

It will be taken off road. A tourer would in no way have been suitable . Just not on a cx racing

I knew the gears were wrong.. I misjudged how easy it would be to swap to suitable gearing due to ridiculous standards on the chain set. But I had budgeted to make this change as the bike was do cheep

As I have already said I have managed to get the appropriate gearing through spending 50 quid on a new mech and cassette. So job done.

Thanks to all those with useful advice...


 
Posted : 06/08/2017 1:09 pm

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