Adressing granny

What is the smallest granny ring that can be fitted to an MTB compact chainset, 94bcd ?

What is the slowest speed one can travel at with granny before balance becomes a problem ?

Is it forward motion that maintains balance, or is there a minimum speed ?

Q - What is the smallest granny ring that can be fitted to an MTB compact chainset, 94bcd ?
A - Sorry no idea


Q - What is the slowest speed one can travel at with granny before balance becomes a problem ?
A - Very slow, i guess I would get board before falling over.

Q - Is it forward motion that maintains balance, or is there a minimum speed ?
A - I am sure some one with a better grasp of Phisics (or at least someone who can spell it) will explain this. If you track stand there is no forward speed, I once did a 12min trackstand and can still do traffic lights and level crossings with out putting my feet down

You maintain balance at still, as speed increases the wheels spinning help out at an increasing rate. You'll still fall off it you don't help maintain the balance.

silverclaws":3gr9kbun said:

What is the smallest granny ring that can be fitted to an MTB compact chainset, 94bcd ?

What is the slowest speed one can travel at with granny before balance becomes a problem ?

Is it forward motion that maintains balance, or is there a minimum speed ?

Click to expand...

Smallest granny ring that can be fitted to a CD crankset is, I believe, 20 tooth.
As far as the "slowest speed possible" using really low gearing, this depends mostly on the surface. On smooth tarmac you could go pretty much as slow as you liked (.5 - 1mph) but once you get on to the varied surfaces off road then at those sort of speeds a small rock, a patch of mud or a branch to cross would be enough to cause you a problem without some sensible sort of momentum to carry you over.
So 20T might be useful for "rock crawling" type of riding but for anywhere that traction is an issue very low gearing doesn't work on an mtb, or any other vehicle for that matter. A bit of momentum, along with higher gearing, is usually your friend.

Forward motion (ie the gyro effect of revolving wheels) does help to keep a moving bike upright, but at very low speeds this effect is negligible and balance is maintained by minute steering changes (you steer into the direction your body feels it is falling) and changes in weight distribution. The steering effects are very real part of staying upright - try riding a bike with seized steering or (to confuse the brain) with your arms crossed.

http://www.retrobike.co.uk/forum/viewto ... highlight=

The last youtube vid show how slow you can go with balance. The girl knows how to ride a bike

On my Lloyd I run a 20 at the front and a 30 at the back = 16.8 gear inches.
Very similar to modern 22 front and 34 back = 16.3 gear inches.

If you went 20 x 34 = 14.8 gear inches.

On my scary Nicolai with the Rohloff I use a 34 tooth front and 16 on the hub which = 15 gear inches - This thing weighs about 38 lbs!

The point of this... I find having very low gears useful. It's not necessarily that I use them to go very slowly uphill, what I tend to do with them is spin them fast to keep momentum going whilst staying seated to maintain traction and stability. This means I get knocked off line less and suffer less stalling when winching/riding through steep uphill rock gardens. I also use them to back off on the smooth parts of climbs so I can regain my breath to tackle the next rocky bit ahead. The challenge of riding these trails is awesome and I love it. I've met very few riders who are capable of riding up some of these paths and put that down to my technique and use of these low gears. I don't like walking if it's at all possible to ride...

messiah":3ryjed7s said:

The point of this... I find having very low gears useful. It's not necessarily that I use them to go very slowly uphill, what I tend to do with them is spin them fast to keep momentum going whilst staying seated to maintain traction and stability. This means I get knocked off line less and suffer less stalling when winching/riding through steep uphill rock gardens. I also use them to back off on the smooth parts of climbs so I can regain my breath to tackle the next rocky bit ahead. The challenge of riding these trails is awesome and I love it. I've met very few riders who are capable of riding up some of these paths and put that down to my technique and use of these low gears. I don't like walking if it's at all possible to ride...

Click to expand...

Don't get me wrong, I sometimes find low gears as useful as the next guy - it's just that what stops me on most climbs is running out of traction and not just the steepness of the gradient. I suppose it's because we don't have much really rocky, grippy going round here and the most difficult climbs (while they can be steep enough :roll: ) are usually a mixture of peaty mud, loose stones and cross roots which are like ice when they're wet.
I just seem to get nowhere fast on these climbs if the gear is too low - like trying to tackle a greasy climb in 1st gear on a trials bike, it's almost impossible not to spin out.
I'm like you though, in that I hate having to walk - I'll winch/grind my way up stuff just to prove that it can be done, even if my mates are as quick pushing up.....