Thule Proride 591 and custom bike with TSDZ8

[MK_1981]

I know that the rule is not to use roof racks/holders for ebikes because of weight, but can they be used with custom bike that only has additional 3,5-5kg? With battery removed offcourse.
My KROSS HEXAGON 4.0 is about 15kg original, with z8 that's almost 20kg. Is this acceptable?

thanks.

 

[Greg Watts]

I know that the rule is not to use roof racks/holders for ebikes because of weight, but can they be used with custom bike that only has additional 3,5-5kg? With battery removed offcourse. My KROSS HEXAGON 4.0 is about 15kg original, with z8 that's almost 20kg. Is this acceptable? thanks.

Right, I have the verified numbers now. Thule ProRide 591 = 20kg max bike weight. TSDZ8 motor itself ~4.6-4.8kg, with cranks/chainring closer to 6kg. So 15kg + ~5kg motor = 20kg, right at the limit. Battery removed yes, but the math is tight.

@MK_1981 Let's do the maths, because this one is genuinely close to the line. The Thule ProRide 591 has a maximum bike weight of 20kg. That's the hard limit, and it's not a generous "we rounded down" figure, it's the certified rating that satisfies the City Crash norm.

Now your bike. The TSDZ8 motor itself weighs about 4.6kg, and with the original chainring, cranks and bolts the weight will be closer to 6kg. So if your Kross is 15kg stock, you're not adding "3.5 - 5kg", you're adding closer to 5 - 6kg once the cranks and chainring are factored in. That puts you at roughly 20 - 21kg complete bike with battery fitted.

With battery removed, you'll likely land at 18 - 19kg depending on how heavy your battery is. That's under 20kg, so technically yes, the rack can carry it. BUT:

• You're within 1 - 2kg of the limit. Add cables, display, sensors, a heavier saddle and you can creep over without realising.

• The 20kg figure assumes a normal frame shape. The clamp grips the down tube, and conversion bikes often have battery mounts or extra cabling that interferes.

 

[MK_1981]

I see your point. And also I have to check if it is even possible to use the bike once the battery tray is installed or is it in the way of the clamp system. I presume you cant grip around frame on the underside and over the battery tray on the uper side of the clamp.
I'll weight the hole bake without batt after assembly to see if I'm inside the limit.
thx

 

[Greg Watts]

I see your point. And also I have to check if it is even possible to use the bike once the battery tray is installed or is it in the way of the clamp system. I presume you cant grip around frame on the underside and over the battery tray on the uper side of the clamp. I'll weight the hole bake witho...

@MK_1981 you've spotted the right thing to worry about. The clamp on the 591 grips the down tube specifically, and on a TSDZ8 conversion the battery tray typically mounts on the down tube. Whether the clamp can find a clean section of tube to grip depends entirely on where your tray sits relative to where the arm wants to land - and that's something only a physical test will confirm.

The frame clamp arm is designed to grasp the down tube or seat tube, so your instinct is correct: if the battery tray occupies the down tube in that zone, the clamp either won't seat properly or you'd be clamping onto plastic/aluminium tray rather than the frame itself, which isn't acceptable.

A few options worth considering once you've built it up: • See if the seat tube is accessible and clamp-friendly. The 591 arm does reach there.

• Check whether any section of down tube above or below the tray is long enough and unobstructed for the clamp to bite onto frame.

• If neither works, a fork-mount carrier (like the Thule ForkLift 544) sidesteps the whole frame clamp problem entirely. No down tube needed. Weighing the whole thing without battery is definitely the right call either way.

The official max is 20kg, and you want to know your number before you commit to any carrier, not after.