Rear suspension w/ Cate motorcycle carrier

Wilso122_t61-coast · Nov 12, 2022

Hi there, Need some input from suspenders experts please.

Just about to pick up the new to me Cali and bought a cate motorcycle rear rack from the bay.

I know I’m going to be right on the axle limit and handling will be effected, possible tailgate won’t open etc, just trying to find some wisdom on the rear springs and possible options. First some details.

Model - 2021 California Coast.
Additional Cate rear motorcycle rack 20-30kg
Enduro motorcycle 140kg with fuel.
Inside will be motorcycle kit about another 50-100kg.
+ usual things that will live inside.
Standard 16” wheels and tyres.
The rack and Motorbike will not always be on the back when out with kids camping etc or the rack there with a cycles/ storage box.

To balance I will move the rear seat as far as possible forward and distribute internal weight evenly if not biased to front.

In the 2021 coast are they t28, 30 or 32 springs?

Given the above what should I look to do for rear springs so the arse doesn’t ground out on any bump. Or would stock suspension be enough or upgrade to t32 springs if not already in.

Thanks a lot.

gavinbalfour · Apr 21, 2024

Hi, no expert but did this rough calc recently for a similar reason. Follow the calculation shown in the image and use the dimensions from the van image. Your calculation is going to be distance of load from front axle (3000mm wheelbase plus the 993mm to the end of the rear bumper where the rack will be) = 3993mm. Divide this by the wheelbase which is 3000mm. This gives you a figure of 1.331. Then multiply 1.331 by the weight of the rack and the bike combined of 170kg which equals an additional 226kg on the rear axle.

The maximum weight allowable load on your rear axle from the weights table image (for a Surf which I think is the new Coast?) is 1575kg.

You then need to find out what the actual current weight on your rear axle is by going to a public weighbridge (They charge about £20) or maybe someone on here has that figure for a Coast. You need to do this with the van full of expected passengers and all your camping and bike kit so you know the total current rear axle weight when fully loaded. Add the additonal 226kg to the current weight on the rear axle. You need that overall figure to be less than the maximum rear axle load of 1575kg.