I have been trying to adjust the spring preload and understand that to do so I need to measure how much the suspension is compressed and compare that to the total travel of the suspension.
Does anyone know what the total travel of the suspension is on a stock R1200R?
Thanks very much for any help you can provide.
Total travel of suspension
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deilenberger
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The manuals and BMW writeups give what I consider to be somewhat optimistic travel dimensions. I did measurements myself with the suspension when I installed the Hyperpro suspension shocks/springs.
Quick way to find the front suspension total travel.. put a tie-wrap around the fork tube. Slide it down to the top of the slider. Go for a ride and try to find some big bumps. Get off and measure the distance between the bottom of the tie-wrap and the top of the fork slider. That's your total travel. You can then use the same tie-wrap (forget if the front suspension preload is adjustable..) to measure your static and dynamic sag.
Recommended dynamic sag (you on the bike on tip-toes - no weight on your toes) is usually about 1/3rd the travel. That worked well on my Hyperpro shocks - front and rear. IMHO - static sag really has no meaning since your suspension really isn't important with you off the bike.. DYNAMIC is the important number.
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Front travel - BMW claims 120mm (4.7").
IF that number is correct - 40mm of dynamic sag is your target. I suspect the actual travel is less - and would be interested in what you measure if you use the tie-wrap measurements (I didn't measure this before fitting my Hyperpros - which have less travel since it's a slightly shorter shock..)
Rear travel - BMW claims 140mm (5.5").
I measured the stock rear shock travel, then I calculated the lever arm between the pivot point on the swingarm, the shock position and the rear wheel. It's a 3:1 ratio.. in other words, for 1mm of shock travel, the rear wheel will move 3mm.
I measured the stock rear shock as having 47mm of possible travel (shock makers do not deduct the rubber bottoming bumper on the shaft - that's included in travel) - which gives 125mm of rear travel for the stock rear suspension.
BMW claim of 140mm (5.5") - I think is optimistic. The 125mm is a more realistic number. Using that number - 42mm is a good dynamic sag to shoot for.
NOTE - rear dynamic sag is much more changed by differing loads on the bike. Since most weight added on a bike when travelling is towards or over the rear wheel - that is the end where the suspension preload is going to change dramatically with weight. It's also why BMW put the hydraulic preload adjuster on the rear.
HTH.. more than you wanted to know prolly..
Quick way to find the front suspension total travel.. put a tie-wrap around the fork tube. Slide it down to the top of the slider. Go for a ride and try to find some big bumps. Get off and measure the distance between the bottom of the tie-wrap and the top of the fork slider. That's your total travel. You can then use the same tie-wrap (forget if the front suspension preload is adjustable..) to measure your static and dynamic sag.
Recommended dynamic sag (you on the bike on tip-toes - no weight on your toes) is usually about 1/3rd the travel. That worked well on my Hyperpro shocks - front and rear. IMHO - static sag really has no meaning since your suspension really isn't important with you off the bike.. DYNAMIC is the important number.
===========================================
Front travel - BMW claims 120mm (4.7").
IF that number is correct - 40mm of dynamic sag is your target. I suspect the actual travel is less - and would be interested in what you measure if you use the tie-wrap measurements (I didn't measure this before fitting my Hyperpros - which have less travel since it's a slightly shorter shock..)
Rear travel - BMW claims 140mm (5.5").
I measured the stock rear shock travel, then I calculated the lever arm between the pivot point on the swingarm, the shock position and the rear wheel. It's a 3:1 ratio.. in other words, for 1mm of shock travel, the rear wheel will move 3mm.
I measured the stock rear shock as having 47mm of possible travel (shock makers do not deduct the rubber bottoming bumper on the shaft - that's included in travel) - which gives 125mm of rear travel for the stock rear suspension.
BMW claim of 140mm (5.5") - I think is optimistic. The 125mm is a more realistic number. Using that number - 42mm is a good dynamic sag to shoot for.
NOTE - rear dynamic sag is much more changed by differing loads on the bike. Since most weight added on a bike when travelling is towards or over the rear wheel - that is the end where the suspension preload is going to change dramatically with weight. It's also why BMW put the hydraulic preload adjuster on the rear.
HTH.. more than you wanted to know prolly..
Don Eilenberger - NJ Shore
2012 R1200R - I love this bike!
2012 R1200R - I love this bike!