# Modern MTB gearing set-ups for dummies.......



## I like Skol (29 Jun 2013)

I keep thinking that at some point in the near future I am going to 'upgrade' my 20yr old MTB to a modern gear set (been thinking this for nearly 2 years ).

Currently running a 3x8 set up that started life as Shimano XT but over time has drifted down spec as 8spd parts dried up. Thinking about the way I use my current gears and the range of gears available with current cassettes and chainsets I am strongly tempted to ditch the triple for a double. I am also reluctant to go to a 10spd cassette when I have seen suggestions that the 8/9spd chains are more robust than the super narrow 10spd variant. 9spd also means I have standard chains across my 3 bikes and I never find myself wanting more gears on my 8spd MTB.

My main questions are-

Is 9spd more robust than 10spd so should I try and get 9spd shifters while they are still available in XT?
Will a 10spd chainset run with a 9spd chain ok or am I destined for rubbing and ghost shifting at the front due to the wider chain? I can only see 10spd XT chainsets (double and triple) available and would prefer to stay with XT.
All help, advice and experience gratefully received.

Skol.


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## fossyant (29 Jun 2013)

10 speed chainset will be fine with 9 speed chains.


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## potsy (29 Jun 2013)

Are you two old duffers not running 11 speed yet?


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## RecordAceFromNew (29 Jun 2013)

I like Skol said:


> I never find myself wanting more gears on my 8spd MTB.


 
Unless your right shifter is gone, why change from 8 speed? Even if it is gone you can certainly get perfectly decent new ones from Shimano. The thing is 8 speed chains are generally tougher than 9, and 9 more robust than 10 etc. Also you can get great 8 speed cassettes for peanuts (e.g. sram PG850 11-32 is only 275g, while some similar level 9 speed cassettes weigh nearly 400g).

You can use any speed chainset with your existing system, all you need to do is to maintain a similar chainline.

If you want to stick with a high groupset and period, XTR m950 8 speed brifters are amongst the lightest, nicest brifters money can buy (secondhand only obviously), and they can only increase in value over time.


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## Cubist (29 Jun 2013)

Or go 2x9 using xt m770 secondhand . All the 9 spd shifters are compatible, and loads available via classifieds.


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## I like Skol (30 Jun 2013)

RecordAceFromNew said:


> Unless your right shifter is gone, why change from 8 speed? Even if it is gone you can certainly get perfectly decent new ones from Shimano. The thing is 8 speed chains are generally tougher than 9, and 9 more robust than 10 etc. Also you can get great 8 speed cassettes for peanuts (e.g. sram PG850 11-32 is only 275g, while some similar level 9 speed cassettes weigh nearly 400g).


I fitted 8 speed Alivio Brifters about 18 months ago because my XT units were shot and I've regretted it ever since. The shifters aren't too bad but the brakes are terrible. Not nearly as much power as my old 1990's set with the moving cam cable pull.



Cubist said:


> Or go 2x9 using xt m770 secondhand . All the 9 spd shifters are compatible, and loads available via classifieds.


 This is what I am thinking. A 2x9 set-up will suit my needs perfectly, 9spd XT M770 shifters are still available new and with an M785 28/40T chainset and a 34-11 cassette I will be pretty much where I am now with my 3x8 set up.

All parts need to be new! I am also tempted to try a 1x9 or 10 just to be radical. I reckon I could live wuith a 38T chainring and an 11-36 cassette?


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## Cubist (30 Jun 2013)

It's your money of course, and I love XT, ..... BUT. You can get SLX 2x10 cranksets from Bike-Discount.de for 125 euros posted. SLX is, thanks to trickle down technology about 40 grammes heavier than XT equivalent! 


My full thoughts are this. 10 speed is plenty robust, unless you are a huge fat knacker who stands up all day to mash your bike up cliff-faces. The flat-earthers will bang on about gossamer thin chains but it's been around as a standard for quite a while, and I don't see many "my chain snapped 'cos it's too thin" threads. 

The shimano 2x10 range are 38/24 and 40/26. The _dedicated _ front mechs are designed to run those combinations (albeit with a 14 tooth difference max.... I run mine 38 24 'cos I'm old and knackered). Mixing and matching may work, but may also give you chainline issues, rubbing and trimming headaches. Using a 9 speed mech other than an SLX 2x9 front is possible, but you'll have to limit the throw, and bugger with clamping height. 

2x10 cranks are cheaper than 9 speed triples when bought from the Germans. OK, cassettes and chains are dearer, as are the shifters, but not by much, and Dynasis 10 spd shifters are all compatible with each groupset, so you could, to bring costs in line, run an XT with Deore shifters and mechs. 

Next alternative is a triple 9 speed converted to double and bash. There are plenty of 9 speed triples left, and it's a simple case of removing the 44t outer and replacing it with a bashguard. I did just this, and replaced the middle 32 with a 36 to give a better spread of gears. Chainline issues are a thing of the past (although I did get an SLX double front mech ..... see above) 

Chain retention is sorted by way of a Blackspire Stinger, although if you went full new 10 speed you'd be able to use a clutched mech to stop slap. 

If you go 1x10 you have the options of up to 36 t cassette. General consensus is that you drop the granny from an XT 2x10. Again, chain retention is a necessity here, as you'll need a chain device, BB mounted or ISCG tabs on your frame to fit one. Therefore to my way of thinking no weight saved, just a bit of simplicity, and I'm an old fat knacker and already have to get off and push up some stuff running a 22-34 bottom gear! 

My recommendation would be complete 10 speed in new SLX, bought from ze germans or french sites. 
http://www.bike-discount.de/shop/k407/a51795/xt-m785-no-brakes-groupset-2x10-speed-40-28-black.html

SLX cranks.... tell me they don't look gorgeous
http://www.bike-discount.de/shop/k407/a51795/xt-m785-no-brakes-groupset-2x10-speed-40-28-black.html

cheaper here http://www.hibike.de/shop/product/p...-incl-bottom-bracket-FC-M675-RETAIL-pack.html

In fact, forget all of that , get one of these before they sell out. Astonishing value, and even includes a shadow plus clutched mech. Why bugger about? 
http://www.merlincycles.com/bike-sh.../shimano-xt-double-transmission-groupset.html
as


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## RecordAceFromNew (30 Jun 2013)

I like Skol said:


> I fitted 8 speed Alivio Brifters about 18 months ago because my XT units were shot and I've regretted it ever since. The shifters aren't too bad but the brakes are terrible. *Not nearly as much power as my old 1990's set with the moving cam cable pull.*


 

If you are talking about the servowave levers I think the feature is no longer available on modern cable levers. If braking power is poor for standard V brakes the reason might well lie elsewhere (cabling/pads/rim clearance etc.).



Cubist said:


> My full thoughts are this. 10 speed is plenty robust, unless you are a huge fat knacker who stands up all day to mash your bike up cliff-faces. The flat-earthers will bang on about gossamer thin chains but it's been around as a standard for quite a while, and I don't see many "my chain snapped 'cos it's too thin" threads.


 

You don’t see many “my chain snapped 'cos it's too thin" threads only because not many chains snap, and that the key user concern with chains is wear rather than breakage (well to those who ride more than talking about their bikes anyway...).

All else being equal, one would be foolhardy to believe 10 speed chains can be as robust/durable as 9 speed, and 9 speed as robust/durable as 8. The reason is as obvious as it is common to find experience in threads confirming it - chain stretch/wear is mainly due to wear on the rivets and “bushings” as Sheldon demonstrated, and the shorter rivets and “bushings” of a narrow chain simply don’t have as much material available to resist the load, and available to be worn away as a thicker chain.


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## Cubist (30 Jun 2013)

No one is pretending they are as robust, but a chain is a consumable. I ride til stuff wears out and then replace it. I like the weight, looks and sweet shifting of my 2x10 setup. If the chain needs replacing I replace it.


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## marzjennings (30 Jun 2013)

RecordAceFromNew said:


> All else being equal, one would be foolhardy to believe 10 speed chains can be as robust/durable as 9 speed, and 9 speed as robust/durable as 8. The reason is as obvious as it is common to find experience in threads confirming it - chain stretch/wear is mainly due to wear on the rivets and “bushings” as Sheldon demonstrated, and the shorter rivets and “bushings” of a narrow chain simply don’t have as much material available to resist the load, and available to be worn away as a thicker chain.


 

I've been riding 10 speed (1x10) for about a year and so far with fewer problems than my old 9 speed. And I've seen nothing tangible to say that the new 10 speeds are less robust than 9s except a few folks speculating on something they've not even tested.

Here's a link to 'test' that shows 10's outperforming 9's ... link


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## RecordAceFromNew (30 Jun 2013)

Cubist said:


> No one is pretending they are as robust


 

Good to know you can see one does not have to be a fat knacker who subscribes to flat earth to want to avoid 9/10 speed chains then.


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## Cubist (30 Jun 2013)

If you want to run 8 speed then crack on old luv.


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## RecordAceFromNew (30 Jun 2013)

Me? Chains I run range from 1/8" to 10 speed at present. They all have their place.


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## Cubist (30 Jun 2013)

Then why are you being belligerent?


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## RecordAceFromNew (30 Jun 2013)

Cubist said:


> Then why are you being belligerent?


 

Belligerent? I suspect you are taking what I wrote too personally when they are not meant to be. To me with chains it is horses for courses, but I do have the feeling that the march of the number of rear sprockets to infinity and beyond is oversold, and not necessarily for the benefit of the vast majority of cyclists.


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## 02GF74 (30 Jun 2013)

3x8 to 3x9 is no big deal , but 2x10???

going to 2x10 will lose the big gears, that are important if you do a lot of downhills on roads and also the small gears; I ditched 2x10 as I was missing out on the small gears - ok, I could have put on smaller chainring on the front but wanted to keep one gear system on my bikes.


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## Cubist (30 Jun 2013)

02GF74 said:


> 3x8 to 3x9 is no big deal , but 2x10???
> 
> going to 2x10 will lose the big gears, that are important if you do a lot of downhills on roads and also the small gears; I ditched 2x10 as I was missing out on the small gears - ok, I could have put on smaller chainring on the front but wanted to keep one gear system on my bikes.


 
My XT 2x10 is 38, 26 front, 11-36 rear in standard form. Being a big fat knacker I put a 24t granny on it. The cassette is 11-36, so it has almost exactly the same bottom gear, 24-36 as my old 9 speed triple conversion which is 22-34. 

38-11 top gear is 106. inches on that setup with 2.4 tyres. A triple with a 42 front would be 117 inches. XT also comes with a 40t front ring, so 111 inches with the same cassette. So you're losing what, half a gear to a full gear?

My Cotic is running a 2x9 converted from a triple XT. I swapped the middle ring for a 36T and kept the granny at 22. The cassette is 11-34. Yes, you spin out on steep road hills, but I seriously don't miss the big ring.


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## I like Skol (1 Jul 2013)

Well! Lots of 'advice' and some lively debate but it all sort of confirms what I suspected in the first place.

My riding style means I rarely leave the middle ring which is currently a 38T. Only really go to the big 48T to take up the chain slack for rough downhill runs or fast tarmac downhills. I also only use the 28T granny ring occasionally when it gets really steep/technical, most of the time my legs do the talking through a 38x(32)28 gear!

Doing the numbers has just given me a bit of a shock . I just counted the teeth on all the cassette sprockets to compare what a 2x9 set up would give in comparison and the shock discovery that I am actually running an11-28 cassette. I should have known because I fitted it but how old skool is that? I'm a monster!!!

A 2x9 set up that would best suit me is a 40/28 chainset and an 11-34 cassette. This gives me a 40/34 gear which is a good bit easier than the 38/28 easiest gear I have when on the middle chainring of my existing gears. It also gives me a 40/11 which lands just between gear 6 and 7 of the 48T chainring range I already have. I think this is a compromise I can accept. I also get a granny ring gear range that will be waaaaaaaaaay more spinney than I am used to but can be a useful 'get out of jail option'.

Now the gear ratios are sorted I just need to decide how to achieve this.

Chainset

Use existing Truvativ Isoflow Trekking arms with new 40 and 28 (30?) rings and maybe a bash guard in place of the existing 48T
Shimano XT M785 40/28
Cassette

Shimano or Sram 9spd 11-34 for HG61/PG950/PG970
Shifters

XT M770 9spd right hand shifter
M770 left hand 3spd shifter restricted to only 2 clicks
M780 left hand selectable 2 or 3 speed
Rear mech

Existing SLX shadow M662 GS
New XT M772 Shadow
New XT M771 traditional
Front mech

Existing XT 1990's
New XT M771 conventional 9spd
 
Mixed in with all this will be new wheels and disc brakes, either at the same time as the gear upgrade or a phase II once the gears are installed and running well.

What do the wise and knowledgeable CC'rs say?

I am only considering sticking with the existing cranks because this allows me to retain the bombproof UN55 square taper bottom bracket. My experience of HTII hasn't been impressive on my commuter machine although that has just been upgraded from the entry level BB51 model for an XT BB70 one so I can't comment on if that is any better yet?

I would happily run odd shifters to get the selectable 2/3 gear left hand M780 version and an M770 right hand 9spd but can't seem to find the left M780 for sale separately so might end up running the M770 3spd on the left with only 2 cogs?


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## lukesdad (1 Jul 2013)

Late to this but would go square taper 1x9 36t (11-34) deore disc middleburn crank .


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## dan_bo (3 Jul 2013)

I'm running an 8 block on 7sp thumbies!


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## I like Skol (3 Jul 2013)

dan_bo said:


> I'm running an 8 block on 7sp thumbies!


 Thumbies! Wot are them granddad? 
DX and XT thumb shifters were THE sought after item for a long time after rapidfire was introduced.


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## dan_bo (3 Jul 2013)

I like Skol said:


> Thumbies! Wot are them granddad?
> DX and XT thumb shifters were THE sought after item for a long time after rapidfire was introduced.


 
And they still work a treat bra! they're 24-*24*- years old. I've had them on 4 bikes and they still click through.

Thar's design and materials for ya.


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