what happened to the big ring?

fredy

i've noticed that bigger bikes (AM/ some DH) have ditched the big ring, and in the case of AM, have left the granny ring. I have never used the granny ring but when going downhill i always use the big ring for extra speed and control. Why have bigger bikes that are designs to go fast down hill disregarded the big chainring?

Deputy Dawg

Clearance probably.

jay12

basically you have bigger clearance from obstacles. most people run rings that are 36t or 38t or a bit smaller. freeriders and downhiller only use one ring and so do 4x riders. am riders tend to use two rings and a ratio of 24t and 36t rings are popular as you only waste 1 or 2 gear ratios but won't risk breaking the big ring

Buckled_Rims

As mentioned, extra clearance.

Also, I think there's a school of thought that you can increase acceleration on a 36t far better and more instant then a 42/44t for many downhill sections. I'm also not really sure if many downhill racers can be bothered changing up to a big cog from the middle as it can take almost 1 second to throw the chain up.

Northwind

Buckled_Rims wrote:

I'm also not really sure if many downhill racers can be bothered changing up to a big cog from the middle as it can take almost 1 second to throw the chain up.

DH racers pedal themselves into a smoking wreck without needing higher gears. But they use single ring mainly to stop the chain dropping off I think.

The other reason the big ring's vanishing off smaller bikes, Pitch Pros and the like, is that it's not all that useful and it costs you ground clearance. Without getting into the same debate (again!) you don't lose all the gears from the big ring, if you go double with a 36T biggest ring you get all but the very last 2 gears which would have been on a 44T.

fredy

but i like those last 2

Mancunianfightingcat

Down hillers don't need as big a gear spread, if you look at their rear cassette, many fit road bike cassettes, which are higher geared to compensate for the lower front gear.

Mancunianfightingcat

Down hillers don't need as big a gear spread, if you look at their rear cassette, many fit road bike cassettes, which are higher geared to compensate for the lower front gear.

Anonymous

Mancunianfightingcat wrote:

Down hillers don't need as big a gear spread, if you look at their rear cassette, many fit road bike cassettes, which are higher geared to compensate for the lower front gear.

No they're not. Smallest sprocket is the same size.
The spread from largest sprokcket to smallest is reuced though, meaning there's less gap between each gear.

Mancunianfightingcat

Yeah, but how often would you go 44T and then 11 or 12 at the rear?

Anonymous

makes no difference. You said they fit road cassettes, which are higher geared - they're not. Top gear is the same.

Mancunianfightingcat

Bottom gear on a road cassette is higher than bottom gear on an mtb cassette!

I'm no downhiller, but I guess they don't just bang it in top and leave it there, therefore, their choice of gears are all higher (or equal) to what they'd have if they used an MTB cassette.

peter413

Mancunianfightingcat wrote:

Bottom gear on a road cassette is higher than bottom gear on an mtb cassette!

11 and 11. How is that higher

Road cassettes also run 12 sometimes but that is technically lower I believe since you can't go as quick with the same cadence

Anonymous

Oh right, I see what you mean now.
The speeds they get up to would suggest that pedalling would be pointless in the faster sections though.
So, I think what the idea is, is to use the pedals for accelerating out of slower sections, to get back up to silly speeds. The single chainring allows the use of a full chainguide to prevent chain loss.

Still, it would be interesting to see some of the more powerful pedalers use a double setup, say a 38t, and a 46 to try and get even more speed on the very fastest sections.

Anonymous

peter413 wrote:

Mancunianfightingcat wrote:

Bottom gear on a road cassette is higher than bottom gear on an mtb cassette!

11 and 11. How is that higher

Road cassettes also run 12 sometimes but that is technically lower I believe since you can't go as quick with the same cadence

Bottom gear would be the largest sprocket :roll:

peter413

yeehaamcgee wrote:

Still, it would be interesting to see some of the more powerful pedalers use a double setup, say a 38t, and a 46 to try and get even more speed on the very fastest sections.

Now you mention that, Truvativ, please make your Hamerschidt (oops, thanks yeehaamcgee) with a 38t ring so that you can still run a full guide and they will have an even higher gear than a 38 but still just as much clearance

peter413

yeehaamcgee wrote:

peter413 wrote:

Mancunianfightingcat wrote:

Bottom gear on a road cassette is higher than bottom gear on an mtb cassette!

11 and 11. How is that higher

Road cassettes also run 12 sometimes but that is technically lower I believe since you can't go as quick with the same cadence

Bottom gear would be the largest sprocket :roll:

Well in that case, he may still be wrong because of the closer ratio cassettes and stuff and then how many speeds you are running etc etc

Anonymous

peter413 wrote:

Now you mention that, Truvativ, please make your Hussefelt with a 38t ring so that you can still run a full guide and they will have an even higher gear than a 38 but still just as much clearance

Hell yes! (I'm guessing you mean the Hammerschmidt though)
Is that how the Hammer system works, you get a higher gear than the size of the chainring? If so, that would be great for DHers - but sadly I suspect you're mistaken again and that it works the other way around.
Even so, nothing wrong with making a 46t hammerschmidt, which can also behave like a 38, it would still give the same benefit

peter413

yeehaamcgee wrote:

peter413 wrote:

Now you mention that, Truvativ, please make your Hussefelt with a 38t ring so that you can still run a full guide and they will have an even higher gear than a 38 but still just as much clearance

Hell yes! (I'm guessing you mean the Hammerschmidt though)
Is that how the Hammer system works, you get a higher gear than the size of the chainring? If so, that would be great for DHers - but sadly I suspect you're mistaken again and that it works the other way around.
Even so, nothing wrong with making a 46t hammerschmidt, which can also behave like a 38, it would still give the same benefit

Nope, the mechanism works by giving you the ordinary ring and then an overdrive system that gives you 1.8 (I think its that number ) revolutions for every revolution of the cranks

Raymondavalon

jay12 wrote:

basically you have bigger clearance from obstacles. most people run rings that are 36t or 38t or a bit smaller. freeriders and downhiller only use one ring and so do 4x riders. am riders tend to use two rings and a ratio of 24t and 36t rings are popular as you only waste 1 or 2 gear ratios but won't risk breaking the big ring

I have a triple ring AM, but I barely use the 44T chainring when at Cannock Chase or Swinley Forest.
My new build will use a double chainring setup, not just for clearance but for the simple fact that I hardly use the 44T chainring. I believe the ratio of 36/24 should be more than ample

Anonymous

peter413 wrote:

Nope, the mechanism works by giving you the ordinary ring and then an overdrive system that gives you 1.8 (I think its that number ) revolutions for every revolution of the cranks

Ah, that is wicked then.
Hmm, I might be looking into this Hammerschmidt in more detail for the next Alps trip.

fredy

Raymondavalon wrote:

jay12 wrote:

basically you have bigger clearance from obstacles. most people run rings that are 36t or 38t or a bit smaller. freeriders and downhiller only use one ring and so do 4x riders. am riders tend to use two rings and a ratio of 24t and 36t rings are popular as you only waste 1 or 2 gear ratios but won't risk breaking the big ring

I have a triple ring AM, but I barely use the 44T chainring when at Cannock Chase or Swinley Forest.
My new build will use a double chainring setup, not just for clearance but for the simple fact that I hardly use the 44T chainring. I believe the ratio of 36/24 should be more than ample

but how often do you use the 24 ring?

ESHER SHORE

I run 36T / 28T with a Gamut bashguard at the front of my All-Mountain bike

and 11-34T 9 speed at the rear

I have never "spun out" going down a hill, and find this combination of gears is brilliant for all round riding including going UP hills, ALONG singletrack, and DOWN the hills!

on other bikes where I have run a 38T single ring at the front (with a suitable chain device) and gone to bike park like Whistler in Canada, I have never spun-out of gears going down much bigger runs than anything in the UK, in Whistler you are braking, not pedalling, in many instances!!

the bash guard on a dual ring setup gives you the ability to run into trail obstacles like logs and rocks without ruining your drivetrain

jay12

Raymondavalon wrote:

jay12 wrote:

basically you have bigger clearance from obstacles. most people run rings that are 36t or 38t or a bit smaller. freeriders and downhiller only use one ring and so do 4x riders. am riders tend to use two rings and a ratio of 24t and 36t rings are popular as you only waste 1 or 2 gear ratios but won't risk breaking the big ring

I have a triple ring AM, but I barely use the 44T chainring when at Cannock Chase or Swinley Forest.
My new build will use a double chainring setup, not just for clearance but for the simple fact that I hardly use the 44T chainring. I believe the ratio of 36/24 should be more than ample

i use 36/22 as i cba changing the smallest ring to 24 and 95% of the time i use the 36t ring anyway

jay12

yeehaamcgee wrote:

peter413 wrote:

Nope, the mechanism works by giving you the ordinary ring and then an overdrive system that gives you 1.8 (I think its that number ) revolutions for every revolution of the cranks

Ah, that is wicked then.
Hmm, I might be looking into this Hammerschmidt in more detail for the next Alps trip.

it's an amazing idea BUT way too expensive. if they can make it alot cheaper i would be very interested.

some vids of it and the "science" behind it
http://www.magicmechanics.com/home.php?lang=en#/how_it_was_made/
http://www.magicmechanics.com/home.php?lang=en#/how_it_works/

tony620

I use a SLX double and bash and i do mainly XC and i love it perfect for rolling over logs with

Anonymous

ESHER SHORE wrote:

I run 36T / 28T with a Gamut bashguard at the front of my All-Mountain bike

and 11-34T 9 speed at the rear

I have never "spun out" going down a hill, and find this combination of gears is brilliant for all round riding including going UP hills, ALONG singletrack, and DOWN the hills!

Hmm, I have a 36 on the front, and an 11 at the back, and I find I spin out all the time. Even when riding on the flat.
I had a 42 on the front in the alps, and was still spinning out.

captainfly

It is a case of compromising between acceleration, speed and reliability. Though of course you can go for a big single ring if you have the power.

christopherw303

I used to ride a Santa Cruz Blur (1st Generation) w/ a Race Face Next LP Carbon Crankset. This crankset came in two options at the time- Standard (46T) and "compact" (44T). Mine had the standard 46T chainring.

Of course, ground clearance on some trails was sometimes a minor issue, but this bike kicked a** on the street! It was way better than a road bike for hopping curbs, potholes, and off-road short cuts-- and it could haul!!

Now that 46T, and even 44T, chainrings are gone from the marketplace, it is a shame b/c mountain bikes are now no longer any good for cross use-- you'll never be able to reach the same top speeds as before.

Thewaylander

Have to say round my locals, (cwm afan and this area) I never get into my 44 ring, and keep wishing i had a 36 with a bash :S

Most trails I ride are to steep and twisty to be able to use a 42, and some of the climbs are so steep t22 tooth is essential. and when riding on rocky areas i have had rocks fly up when on the 42 smashing the chain and breaking it.

I personally can't see a reason where i live to have a 42... But it does depend on the trails your ride. Twisty steep technical and rocky then you jsut don't need a 42.

Chunkers1980

It's just setting bike up for what they are used for.

If racing you've done the course an know what to expect and what is needed - you adjust your bike to the best you can for the conditions.

XC racers will drop the granny if the course does not require it and a 34-34 or 36-36 is the lowest they need.

DHers simply do the same, weigh up the benefits and the cost when they look at what they're riding.

Outside of race where you don't know what you're getting, you need to be equipped for all cirumstances as you don't know 100% exactly what you'll come across.