Front Suspension Tuning?

[Blue Meanie]

Had my BMW G310R for a couple of months now and absolutely love it but for one thing - the 'stock' front suspension set up! Not sure if being assembled in India means they're set up for riders who are 75kg wet through - which I am definitely not - but the front end on my bike feels way too light. I know the stock oil is 7.5W but no idea what the spring rate is. During 'normal' riding, everything is sweet but as soon as I give it some beans, I get quite a bit of uplift under hard acceleration and a bit of diving when hitting the anchors hard!

I'm not a suspension expert by any stretch of the imagination and although I would be willing to have a crack, I'd rather leave it to someone with a decent level of expertise - particularly given the impact getting it wrong could have on the bike's handling. On that note, a mate has suggested Phil Parish who, fortunately, resides in my neck of the woods here in Chch. Anyone used his services & are happy to recommend him or not as the case may be. Any other suspension gurus out there?

[SVboy]

Phil is a very good mechanic and would certainly be able to help sort your spring rates. I know nothing of that BMW[or any BMW] but I assume the front has no adjustment for compression or rebound except playing with fork oil viscosity. You talk of it "springing back" and diving too quickly which is certainly a function of a lack of rebound/compression damping.

[F5 Dave]

I only know Linton down that way, at DAS . I imagine anything that you do will yield benefits on budget suspension. Springs to suit but just going up on fluid viscosity is double edged sword.

That said in the old days the qty of oil youd find from factory in a kawasaki for instance would only be of use to stop the insides rusting.

You could drop some racetech valves in there but cost justification would need consideration.

[malcy25]

Sounds like springs to me (as a min) as the thing is sacking out. Check pages like Racetech.com that sell springs. They usually have a tool which for your bike will show std rate and suggested rate for your weight and use.

Check the amount of chrome leg showing with the front wheel off the ground and when you are on it with your gear. Bet there's like 60-70mm or more difference.

No amount of fiddling with oil weight, height and spring preload will fix a spring rate issue. They will bandaid it, usually with some resultant compromises.

You could also ring KSS in New Plymouth. They may have a drop in spring option and have done a lot of small bike work due to the 300supersport being popular here.

Another solution is talk to Liam at Fastbike gear in Auckland. he has some pretty inventive solutions including a great way to make springs stiffer by removing some coils from use without shortening the springs.

[Robert Taylor]

Sounds like springs to me (as a min) as the thing is sacking out. Check pages like Racetech.com that sell springs. They usually have a tool which for your bike will show std rate and suggested rate for your weight and use.

Check the amount of chrome leg showing with the front wheel off the ground and when you are on it with your gear. Bet there's like 60-70mm or more difference.

No amount of fiddling with oil weight, height and spring preload will fix a spring rate issue. They will bandaid it, usually with some resultant compromises.

You could also ring KSS in New Plymouth. They may have a drop in spring option and have done a lot of small bike work due to the 300supersport being popular here.

Another solution is talk to Liam at Fastbike gear in Auckland. he has some pretty inventive solutions including a great way to make springs stiffer by removing some coils from use without shortening the springs.

There is nothing innovative about any devices that lock off some coils, its been done before, well well before than in a shed in Auckland. A variation of this principle has been employed in Mountain bike forks for many years. The negative implication is that in small bore forks it really messes with the trapped air volume above the set oil level ( if the trapped coils are above the oil level ). Plus you can have a sizeable and highly negative ''oil dipper'' affect in the latter reaches of stroke. And they dont address the other 50% of the issue, poor hydraulic control
When these were introduced this individual picked on a set of poorly adjusted / badly messed with/ well beyond service date Andreani cartridges to make a comparison against, hardly a sincere test. How can you have any vestige of respect for such people that are not totally sincere????? If these were what they were disigenuously claimed to be they would be fully embraced in Supersport 300 national racing in NZ
The gullibility of consumers knows no bounds , yes they will provide some level of improvement . BUT overspringing in ANY form is no substitute for having a proper correlation of spring rate, preload, secondary trapped air spring volume AND a proper damping force curve.

[jellywrestler]

disigenuously

boy am i gonna open a few eyebrows at next mondays scrabble night, thanks Robert.

[Robert Taylor]

boy am i gonna open a few eyebrows at next mondays scrabble night, thanks Robert.

The spelling mistake is noted, but I would have thought you are more attuned to bingo?

[nzspokes]

There is nothing innovative about any devices that lock off some coils, its been done before, well well before than in a shed in Auckland. A variation of this principle has been employed in Mountain bike forks for many years. The negative implication is that in small bore forks it really messes with the trapped air volume above the set oil level ( if the trapped coils are above the oil level ). Plus you can have a sizeable and highly negative ''oil dipper'' affect in the latter reaches of stroke. And they dont address the other 50% of the issue, poor hydraulic control
When these were introduced this individual picked on a set of poorly adjusted / badly messed with/ well beyond service date Andreani cartridges to make a comparison against, hardly a sincere test. How can you have any vestige of respect for such people that are not totally sincere????? If these were what they were disigenuously claimed to be they would be fully embraced in Supersport 300 national racing in NZ
The gullibility of consumers knows no bounds , yes they will provide some level of improvement . BUT overspringing in ANY form is no substitute for having a proper correlation of spring rate, preload, secondary trapped air spring volume AND a proper damping force curve.

Agreed on the coil rate reducer things. On bicycles you ended up with little bits of plastic flying around in the fork legs. But on them oil height etc was not an issue as the damping is in the other leg.

Suspension is not something thats a bodge fix. Just do it right once and be happy.