My Suzuki Smash 110cc had a rear wheel innertube replaced by the local guy in my village. Since then, when the bike goes over even a slight bump in the road, as the bike rises back up from the compression of the rear shock absorbers, it feels like the rear wheel is braking.

This slight braking sensation is momentary, but happens every time there is any undulation in the road surface.

Anyone know what could be causing this?

Maybe the shocks are no good or they were reinstalled incorrectly. This could be causing the top of the tire to rub against the top of the wheel well when you hit bumps. Best of luck.

Thanks for the input. Apologies for my poor explanation of the problem. The tyre isn't touching the wheel arch when the bike goes over a bump or depression in the road I'm sure. There's no mark on the underside of the wheel arch.The shocks don't "bottom out" at all.

The problem occurs just after the undulation in the road and as the shocks react to it. Could the wheel be set too far back on the frame, causing the brake to engage or something? I'm suspecting the guy that replaced the innertube maybe caused a problem when he re-fixed the rear wheel, and was hoping someone may have had a similar experience and could point out the cause. I'm not a bike expert and have only very rudimentary understanding of bike mechanicals. Before the innertube replacement the bike was faultless to ride.

Chain tension and rear brake adjustment would be the first things to check,

I think you can investigate this yourself. Push on the rear brake pedal with your fingers. Does it has any free movement before the brakes are applied?

Look where the back brake cable attaches to the brake mechanism. Can you, with a little effort, move the actuating arm? Unscrew the nut on the end of the cable about half a turn.

Put the bike on the centre stand and rotate the back wheel. See if you can find any resistance.

If you surf you will find lots of info on correct chain tension and how to adjust the rear brakes. Chain tension may require you to go back to the mechanic.

Thanks guys. VocalNeil I did what you explained step by step and was amazed at what I discovered. The rearwheel nuts were loose. They didn't appear to be until I raised the bike on its centre stand. I've tightened the nuts and slightly adjusted the brake and after taking the bike for a quick run it is now back to its usual smooth ride.

So, the whole situation was caused by the guy that replaced the innertube...'nuf said!

Appreciate the help from you guys.

haha, your rear brake was keeping the wheel on. Good design

Now you know why Thais watch their mechanics like hawks!