GT XC2 .. Great bike but issues please help :)

[Theo]

Hi,

I've been using a halfords Apollo 17inch to get around town for a couple of years, and managed to get to considerable speed but it felt so unstable as soon as I took it off road. I've been cycling much more recently and decided to treat myself to a GT agressor XC2 18inch, its amazing and feels so much safer when hitting light trials. But I have two main issues.....

1) I'm 5"7 and fairly stocky so the 17 was a good fit but annoyingly the GT is just slightly too big.. either my feet cant touch the floor if the seats raised or I'm having to yank my knees too high with the seat down.. wondering if theres a solution as I'd hate to see the bike go .. possibly getting a new seat or post or chaning the tyres??? (never modified a bike so dunno where to start.

2) its quite sluggish on road and the only option ive found is to get road tyres but then I cant use it for trials, is there any thing else I can do??

It looks like im moaning about the bike alot but its fantastic, more suited for off road but an actual dream to ride Also if anyone is interested you can get an extra 10% off at halfords if you check myvouchercodes saved me £40!!

Just starting to get into proper trials and cant wait for the summer, thanks for any advice
Theo

 

[Angelfishsolo]

Can you stand over the bike without the top tube compressing parts of your anatomy? If the answer is yes then the bike is ok and you just need to tweek the saddle hight. Answer no and thf frame is too large.

As for performance try 60psi for road use and 40psi for off road.

 

[Norm]

In addition to AFS's comment, sitting on the saddle and trying to touch the floor is not, IMO, a good way to judge the fit. Saddle to pedal is where it's at and get your bum off it's perch when you stop.

 

[Angelfishsolo]

+1. Leg should be at about 95% extension when the pedal is at the 6 o'clock possition.

 

[marzjennings]

On my mountain bikes I can barely touch the ground with tiptoe when seated in the saddle. Changing saddle, seatpost or tyres won't really help. Saddle height is tricky for off road riding. Putting the saddle high enough to maxmise pedaling efficiency can lead to a poor position for negotiating technical trail features.

As mentioned, max out the tyre pressure for the road and drop a few psi when off road. I'm just over 16 stone and ride with 2.5" wide tyres, I run 28-30psi off road and can pump them up for 60psi for the road (thou I don't often bother).

 

[Theo]

Thanks for your advice guys, didnt expect such a quick response!

I just about clear the top tube, and have tweaked it so that I can reach the floor with my toes when on the saddle but it just feels like the gap between the saddle n pedals is too small and im being crammed a little.
To be honest I think I just need to stick it out for a week n see if I adjust to the new riding position. Took it through a forest earlier and it was unbelivable when I was off the seat, never though I could have so much fun on a sunday afternoon.

Will reply again if im still having problems with the size, I've been told by various people that the XC 2 needs some adjustment but i guess its just down to preference.

Thanks again

 

[Cubist]

Theo
You don't need to be in contact with the ground when you're sat on the saddle. Your MTB is designed to have lots of ground clearance to the pedals. It takes a bit of getting used to, but get into the habit of sliding forwards off the saddle before you put your foot down to stop. An 18 inch frame should be OK for a person your size.

 

[Norm]

I'm going to re-quote some posts here, Theo, as I think you missed some important bits.

I just about clear the top tube, and have tweaked it so that I can reach the floor with my toes when on the saddle but it just feels like the gap between the saddle n pedals is too small and im being crammed a little.

As Cubist said, do not even contemplate using the floor to set your seat height. Move off the seat when you stop and the saddle to floor length is completely irrelevant.

As you have said, it doesn't leave enough room for your legs and you will cause yourself damage if you do much cycling with your saddle too low, as it seems to be currently.

As AFS said, the saddle should be set so your leg is almost straight when at the bottom of the pedal stroke.

Do not set the saddle based on being able to reach the floor.

 

[Theo]

Cheers Norm
I will definetly make use of the comments, I know i will have to get off the seat before stopping but tbh it will be hard at first as ive always been a leisure rider.
I feel alot better about keeping the bike now as I would have hated to take it back
Thanks Theo

 

[Norm]

...but tbh it will be hard at first as ive always been a leisure rider.

I know just how that feels, Theo, from being a long-time road rider and permanently in the leisure category myself.

I got myself into the habit of staying out of the saddle on the tricky bits, partly because it makes the bike more manoeuvrable and partly because it's quicker to dab a foot when ambition exceeds ability and it all gets away from me.

 

[Salad Dodger]

I would endorse what Angelfishsolo said in first reply about tyre pressures. I have Continental Mountain King tyres on my MTB which, at about 35 to 40 psi work well on most off-road surfaces (or at least the sort of gentle stuff that I ride on). But at that pressure, riding on tarmac with them is a chore. But pumped up to about 60 psi for the road makes them tolerable. Not as fast as the semi-slicks that I change to in Summer, but tolerable.

Get yourself a good mini-pump, if you haven't already got one, and don't be afraid to use it!

 

[Theo]

Just wondering if 60psi is the sensible max? i always kept between 40-50 with the apollo, hoping 60 will make an improvement with the speed as its a little shamefull at the moment, i got over taken by an old lady in a mobility scooter at the weekend lol.

Does anyone know a good site to find trails in SE england, at the moment im just using google maps and picking parks etc that seem interesting.

 

[Panter]

Just wondering if 60psi is the sensible max? i always kept between 40-50 with the apollo, hoping 60 will make an improvement with the speed as its a little shamefull at the moment, i got over taken by an old lady in a mobility scooter at the weekend lol.

Does anyone know a good site to find trails in SE england, at the moment im just using google maps and picking parks etc that seem interesting.

Where abouts are you Theo? may be able to help with trails if you're local to Kent.
Regarding your tyres on road, you have to accept that off road tyres are always going to slow you on tarmac, it's either something you put up with or buy a second set of wheels (with slicks fitted) so you can chop and change.
Saying that, obviously some tyres are better than others, big, blocky mud tyres for instance will obviously be slower rolling that a fast XC type Summer tyre.


No idea with your tyre pressures, 60 sounds pretty high but your tyres will have an upper limit stamped on them if you want to see if they'll go any higher.
To be honest though, if you're running at 60 now, I doubt you'll see any speed gains by going higher (if you can)

 

[Angelfishsolo]

Sorry for any confusion re: the PSI. Look at the wall of the tyres and you will see and upper and lower limit in bother Bar and PSI. The lower limit I use for off road, the upper for Tarmac. If I know that my ride will be a mis of the two I will set it somewhere inbetween or ever let out some air when I come to the off road section.

As for going higher than 60psi, my Schwable Marathon Plus will run at 75 PSI and they roll like nothing I have felt. They can also make a smooth road feel like a tecnical off road section!

Where abouts are you Theo? may be able to help with trails if you're local to Kent.
Regarding your tyres on road, you have to accept that off road tyres are always going to slow you on tarmac, it's either something you put up with or buy a second set of wheels (with slicks fitted) so you can chop and change.
Saying that, obviously some tyres are better than others, big, blocky mud tyres for instance will obviously be slower rolling that a fast XC type Summer tyre.


No idea with your tyre pressures, 60 sounds pretty high but your tyres will have an upper limit stamped on them if you want to see if they'll go any higher.
To be honest though, if you're running at 60 now, I doubt you'll see any speed gains by going higher (if you can)

 

[Theo]

Just logged back in.. thanks for the response.

I live in Bromley just outside kent, i used to visit canterbury alot and cyle around whistable/herne bay. Is there anywhere you would recomend within a reasonable distance of bromley / chiselhurst?

Cheers Theo

Where abouts are you Theo? may be able to help with trails if you're local to Kent.
Regarding your tyres on road, you have to accept that off road tyres are always going to slow you on tarmac, it's either something you put up with or buy a second set of wheels (with slicks fitted) so you can chop and change.
Saying that, obviously some tyres are better than others, big, blocky mud tyres for instance will obviously be slower rolling that a fast XC type Summer tyre.


No idea with your tyre pressures, 60 sounds pretty high but your tyres will have an upper limit stamped on them if you want to see if they'll go any higher.
To be honest though, if you're running at 60 now, I doubt you'll see any speed gains by going higher (if you can)