Dustdevil
Race Dog
For the BMW R80G/S riders, just some insight into the workings of the G/S forks and why they are so lousy.
1. The fork diameter is a mere 36mm making them very flexible. - not much can be done here besides adding a fork brace or replacing the entire fork at great cost and difficulty.
2. The triple clamp is very insubstantial with the top clamp being made from 3mm steel plate this adding to the flexing problem. - One can fit a handlebar raiser that will also add rigidity to the top yoke.
3. The fork spring is progressive, a 70's concept hardly used by most manufacturers since the 90's. - one can replace these with slightly stiffer linear springs.
The difference between a linear and progressive spring is that the linear spring will have windings with exactly the same spacing between the winding for the entire length of the fork. Progressive springs will have a portion of the windings closer together and a portion of them further apart.
The idea behind progressive springs is that they will provide a softer ride but when you hit a big bump or pothole, the springs will firm up further down into the fork travel and prevent the suspension from bottom out.
This works very well going in a straight line or until you suddenly need to brake hard causing lots of nose diving. Excessive nose diving can be very disconcerting to the rider and possibly prevent the rider from using the brakes to the max increasing the risk of a possible accident.
Progressive springs are often very soft in the initial portion of spring travel and this can also make the bike very nervous in fast cornering especially on an uneven road surface.
The question is, what do you prefer; a comfortable ride that can become hair raising when things suddenly go wrong
or would you rather prefer performance and better feedback from a slightly firmer ride?
Other advantages fitting a stiffer linear spring for the G/S is higher ground clearance, more fork travel and better suited to carry the weight of extra fuel and luggage on longer trips.
The spring that I am having made up will be a 118mm shorter than the standard OEM spring. This means the spring will have to be fitted with a spacer. (My spring will be supplied with the spacer) Having a long spacer have the advantage of easily adding a emulator or even a shorter spring to make the spring slightly softer if a smaller rider finds it to hard. The spacer length can be reduced by exactly the same length as the emulator or spring added.
Specs of new spring is;
Length: 450mm
Preload Spacer: 128mm
Diameter: 26mm
Spring Rate: 0.7 kg/mm or 7 Nm
1. The fork diameter is a mere 36mm making them very flexible. - not much can be done here besides adding a fork brace or replacing the entire fork at great cost and difficulty.
2. The triple clamp is very insubstantial with the top clamp being made from 3mm steel plate this adding to the flexing problem. - One can fit a handlebar raiser that will also add rigidity to the top yoke.
3. The fork spring is progressive, a 70's concept hardly used by most manufacturers since the 90's. - one can replace these with slightly stiffer linear springs.
The difference between a linear and progressive spring is that the linear spring will have windings with exactly the same spacing between the winding for the entire length of the fork. Progressive springs will have a portion of the windings closer together and a portion of them further apart.
The idea behind progressive springs is that they will provide a softer ride but when you hit a big bump or pothole, the springs will firm up further down into the fork travel and prevent the suspension from bottom out.
This works very well going in a straight line or until you suddenly need to brake hard causing lots of nose diving. Excessive nose diving can be very disconcerting to the rider and possibly prevent the rider from using the brakes to the max increasing the risk of a possible accident.
Progressive springs are often very soft in the initial portion of spring travel and this can also make the bike very nervous in fast cornering especially on an uneven road surface.
The question is, what do you prefer; a comfortable ride that can become hair raising when things suddenly go wrong
or would you rather prefer performance and better feedback from a slightly firmer ride?
Other advantages fitting a stiffer linear spring for the G/S is higher ground clearance, more fork travel and better suited to carry the weight of extra fuel and luggage on longer trips.
The spring that I am having made up will be a 118mm shorter than the standard OEM spring. This means the spring will have to be fitted with a spacer. (My spring will be supplied with the spacer) Having a long spacer have the advantage of easily adding a emulator or even a shorter spring to make the spring slightly softer if a smaller rider finds it to hard. The spacer length can be reduced by exactly the same length as the emulator or spring added.
Specs of new spring is;
Length: 450mm
Preload Spacer: 128mm
Diameter: 26mm
Spring Rate: 0.7 kg/mm or 7 Nm
