C650GT Rear suspension Upgrade

A generally accepted recommended setting for motorcycle rear suspension is 15% static sag (no rider) and 25% (passenger and/or rider seated) dynamic sag.

BMW advise the maximum permitted payload is 405 pounds (184 kg) but with this load in place the bike is dangerous as the centre stand frequently grounds. BMW have stated the MK2 versions (2016+) had the suspension retuned for comfort and the spring rates reduced by 10%.

I have been advised the standard spring is 550lb/in (96N/mm). This spring rate is only suitable for an “average” rider of 165 pounds (75Kg) and a light passenger when the preload is adjusted to maximum.

After purchasing the bike new 5 years ago I soon looked for an uprated rear shock absorber and found only Wilbers had one available. The adjustable damping enabled me to compensate for the oil fade over its 24,000 miles (38,00Km) of use. This worked well initially but the mechanical preload adjuster needed tools to adjust it and failed twice, requiring Wilbers to repair it under their 5 year warranty. Arranging this with the UK agent took a long time.

In 2022 Nitron UK listed a rear unit for the BMW C600/C650GT, custom sprung to your requirements and available with a hydraulic preload adjuster, so I ordered one. Nitron Japan provided the dimensions for Nitron UK but their lack of experience with the BMW C650GT required it to be returned twice to modify the spring rates and fittings. I also had to fabricate a small alloy bracket to fit the hydraulic adjuster on the left passenger footboard (see photos). This is a great improvement as I can adjust the preload by hand. I have a 800lbs/inch (140N/mm) spring with 12mm of fitted preload. This is suitable for 220 pound (100Kg) rider and with an additional 12mm preload on the adjuster, a passenger/luggage load of 220 pounds (100Kg). The damping is well controlled and adjustable.

Wow, great to see this in action, and glad to hear you like it.

I did a search recently for shock/fork upgrades for my 650 Sport, and found this Nitron unit, in addition to models from Gears Racing and EMC.

I didn't expect that Nitron UK would have issues with prepping this model, since that's where their HQ is, right?

I'll be curious to hear how it does as you get more miles on it.

Thanks for posting.

Just a FYI - Wilbers in Germany makes a rear shock designed to work on a C650GT . Malossi makes a shock for the C650 Sport , but not the GT model

Here's the link to Germany Wilbers: https://www.wilbers.de/shop/en/Moto...er-type-630-Road-BMW-Telelever.html?year=2015

If you're in the USA here's link to authorized seller : https://www.beemershop.com/product/...l-pre-load-adjustments-c600-sport-c650gt.html

Sadly the cost in USA is much higher, but the Euro is equal to US dollar now so that helps a bit

Hope this helps if you're look to upgrade your suspension ...

Might hace to get that Wilbers sent to my hotel in FRA on my next trip to bring home..

I am interested in upgrading the rear shock on my 2016 C650 Sport. I bought it used to facilitate two up riding with my wife, approx 350 pounds total. On our first rides together she said the suspension seems harsh. Since the GT and Sport appear to have different dimensions I'll move on, maybe start another thread. Good info here though.

husafreak said:

I am interested in upgrading the rear shock on my 2016 C650 Sport. I bought it used to facilitate two up riding with my wife, approx 350 pounds total. On our first rides together she said the suspension seems harsh. Since the GT and Sport appear to have different dimensions I'll move on, maybe start another thread. Good info here though.

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Get the malossi, it has more adjustments and is a very old reputable firm.