How dangerous is bolting a 40L topbox to rear seat?

[Maoser]

I ride a CBR250.

I have a givi rack and Shad 40L topbox.

I saw and read this guy who bolted his to his seat as follows:

Drill holes in seat.

Bolt the holding plate on.

Photos from cbr250.net

Mine is however a bigger box, often with a lot of weight. Often bursts of up to 145kph.

I am quite conscious of the givi rack snapping (they say not to load with over 6kg. The box itself is about 4kg. My stuff could be an extra 5kg.

Safer on the givi rack or safer bolted on the seat?

The last thing I want is the box to go flying off.

Actually the last thing I want is for one side of the givi rack to snap and take me off balance at 145kph before the other side snaps and likely sends me off course and into the ditch on my side.

Thoughts? Ideas? Experiences?

cheers.

 

[bsacbob]

Well i guess how social you want to be and how tall you are, i'm only a short arse and on longer rides i like to slid back on the seat to stretch my legs out, although fixing to the seat would give a nice backrest. As for longevity i would imagine movement of the case / plate on the seat would destroy the fabric.

 

[Maoser]

Sure. I wouldn't worry too much about the fabric to be honest.

I'm not exactly experienced, but I imagine that the weight saving of not having the rack,and the weight distribution - it being on the rear seat and not elevated up behind the bike - would improve the feel of the ride.

But really, I don't know.

I would also guess that over loading would be less of an issue, as there is no rack to snap, but either the whole rear seat would have to come off, or the bolts or plastic of the seat snap.

 

[Thump]

I wouldn't recommend it. Bolting the box on looks straight forward, but then the entire weight is secured by the rear seat.
If weighs a few kg or more when full I wouldn't trust the box to stay on. It might, but I wouldn't feel relaxed riding the bike.
But I like the idea of positioning the box as far forward as possible.
I had a rack built which connects to the frame and secure a simple plastic box with bungee cords.
Did thousands of km with it, even dropped the bike, the box stayed on.
The idea was that since I travel solo I wanted the weight closer to me, not way back, so I installed the box just close enough so that I can move around a bit.
Turned out that a small benefit is that when I carry a backpack it rests on the box, taking the weight off my shoulders.
When I don't go on trips I simply take the rack off; four bolts is all it takes.
Check out your manual to see how much (or little!) weight your sub frame can support, you may be surprised!
For example the 'maximum luggage weight' (which includes the luggage and accessories) for the CRF250L is only - 10lbs or 4,5kg!

 

[Maoser]

Cheers.

 

[prince666]

Hi
on my trip back to China on a Yamaha YBR I loaded up the bike as much as I could , top box Givi had tools and some other stuff 25KG across the back seat had bag with about 40kg in with all the other stuff on top see picture I would say my total kg was close to 90KG ??? with the bike kg of only 130kg made the bike very top heavy to the point of being unsafe..... my back box rack had been modified and my back sub fame has been welded with extra supports. IMO its more importance to check how the bike handles more than how much one can carry , you need to consider the brakes , how good will there stop me how does it handle around bends. bike and me made it back ok to Hainan ok just took a bit longer ????












see the OE rack before i modified it and how the givi top box is not fully supported

 

[lakota]

Wockney, your a Lightweight, you could easily have got another 25 Kg's on the front of the bike using Tank Panniers ;-)

OP, I have the same Shad box on my CB500X . It's a mother out back on the rack. I'd rather travel without it but it's so convenient. you'll certainly feel it at 140kmh. Thumps rack looks the best way to go. you probably won't know the Box is there. If you could make it quick release even better.