Slipping on Fast Bends

[gavintc]

I have a Ribble winter bike - alu framed. It is not new - probably about 5 yrs old. It was 2nd hand. I have never really ridden the bike aggressively until this winter and as my speed and fitness has increased I have noticed that bike does not handle well on fast bends. Initially, I thought this was a result of a worn rear tyre - so replaced it with a new Conti 4000. The problem remains. When I am pushing it and taking a roundabout at about 25 mph, I get a distinct feeling that the back end is not following the front wheel and that it seems to be stepping out. Does anyone else with a winter frame, especially Ribble find this. Is it possible, that I have a frame problem. The frame seems fine when just putting power down on the straight and is only a problem when I am leaning the bike over on a fast bend. It is a little disconcerting.

I do not get this on my summer bike - a carbon Cervelo.

 

[HLaB]

I felt my Sirrus (winter frame) occasionally slip out previously when I had spesh nimbus armadillos (28mm). Ive subsequently replaced the tyres for narrower (25mm) conti 4 seasons and touch wood I've never had a problem with them. However me improving technique may be just as important as (if not more than) the tyre plus the fact that I don't often get 25mph through a roundabout.

 

[Smokin Joe]

I have a Ribble winter and I find it as sure footed as any bike I've ridden. Perhaps the frame has had a knock and is out of line somewhere.

 

[gavintc]

I am beginning to wonder if this is the case.

 

[Gerry Attrick]

I have noticed that some frames have more "road feel" than others. My old hack bike is a heavy dinosaur with little or no feedback from the road and on tight wet bends feels un comfortably like it is going to slip from under me. I get tremendous feedback from my modern machine which gives me the confidence to press on in slippery conditions.

 

[Joe24]

On the 531 frame that used to be fixed, the back felt the same. Like it wasnt following right, ut i just put it down to it being a different frame.
My Giant feel fine though, the back feels like is running well with the front.
Is never stopped me from pushing hard into courners mind, only time i knew i was pushing it too hard was when i felt the back wheel slip out

 

[Dave5N]

My Dolan Ribble did that. I replaced the headset and altered the sadlle position and it's fine now.

 

[02GF74]

When I am pushing it and taking a roundabout at about 25 mph, I get a distinct feeling that the back end is not following the front wheel and that it seems to be stepping out. Does anyone else with a winter frame, especially Ribble find this. Is it possible, that I have a frame problem.

If the frame was out, then it would tend to go off to one side with handlebars pointing forwards as you try to cycle in a straight line.

 

[andy_wrx]

If you're pedalling aggressively and not very fluidly, then with every downstroke you'll reduce the amount of grip the back end has because it's trying to cope with the front-to-rear slip forces generated by you stamping on the pedals as well as the sideways slip forces of cornering.
The front on the other hand is lighter loaded because you have less weight on the front and just has to cope with cornering, not you pedalling as well...

 

[Lardyboy]

How new is the 4000? Has it scrubbed in yet? Mine were appalling until they got worn in.

 

[gavintc]

Thanks for the comments. I was concentrating on it tonight. It is definitely not when I am pedalling and is noticeable when I am leaning the bike into the right hander on the RB. Lardyboy's comment may be appropriate. It has had about 100 miles or so since fitting. I do not notice on the straights just when I am cranking the bike over and it just does not feel smooth and flowing. I intend to take off the wheel tonight and have a good look around the stays.

The headset is new - about 300 miles and the saddle has been in that position all year. It could just be that I have not really pushed the frame to the limit before and I had expected it to feel as solid as my Cervelo - maybe it is just the way of old Ribbles.

 

[andy_wrx]

Yes, agree about Lardyboy's comment.

I bought some new Vittorias 'for the Winter' and they were dreadful, far worse than the squared-off ones with lots of little cuts I was replacing.

But now they're fine, they've worn-in.

There is some residual release-agent left on the tread by the moulding process, plus the moulded rubber itself is a bit slicker, so as they wear-in a bit they gain grip
- but of course you wear-in the centre part of the tread you ride on when straight or on slower bends, a lot quicker than the shoulders you run on when leaned-over cornering...

When you take new tyres to the track, they recommend you rub them over with white vinegar or other solvent to remove the release agent before you go, then you do several laps on the inside of the track or at the black line before you start going up the banking.
Some people even suggest lightly sanding or wire-brushing the tread.

 

[mickle]

It could be something as simple as rear wheel spoke tension, it's highly unlikely that there is anything wrong with the frame, I mean it's either broken or it's not and if it is you'd really know about it.