Im pretty new to biking and new on here so go easy! I could do with some good advice.
I currently have a Specialized Rockhopper 21" frame. Ive always found it a little big so have finally decided to do something about it.
I was thinking of buying a good frame (perhaps a genesis altitude 30) at 19" and transferring all the other bits to the new frame. I could then upgrade other bits to a higher spec over time.
Is this a good idea? or is this doomed to fail?
I could really do with some help here
Cheers

You will find some stuff doesn't fit or needs replacing – seatpost & clamp, front mech,, possibly bb, cables/hoses.

So it can add up, do the sums first!

First of all, make sure the frame your planning on getting will be a fit.

Then, as above work out what will fit & what you will have to replace. Do the sums to see how much the replacement bits will cost & decide if you can afford it/it's worth doing.

On the face of it, it's a good idea, rather than putting up with an ill fitting bike. You can always flog the bits that won't swap over to recoup some of the cost of new parts.

I bought an On One Inbred frame to transfer the bits from my old full sus to, when I replaced it with a new shiny one.
I bought new:
– seatpost (different dia. seat tube) ~£15
– front mech (old frame was e-type mount, not normal band fitment) ~£25
– saddle (not essential, but old one was knackered) ~£23
– bottom bracket (only as old one was knackered) ~£30
– shifters (not essential, but old ones were shagged) ~35

so only £40 of necessary new bits to get it going. Although you'll probably want new cables too.
Just make sure you have enough steerer tube length for the new frame. A new fork could get pricey….

If you are fancying Full Sus – give me an email (its in my profile). Goat frame that would transfer everything from the spesh onto

If you have the knowhow to do it and like a good tinker then why not? Make sure you check the headtube lenthy to make sure your forks will fit (shouldn't be a problem but better safe than sorry), checked your BB shell width is the same, maybe have a check on the hose routing on a new frame to make sure your brake hoses will be okay and be prepared to recable the mechs but you should be fine.

Rockhoppers are great, I had the 2007 M4 version and it rode better than many other things i'd tried before or after. I was hard pushed to find a single difference between that and the M5 Stumpy from a year or two before.

If price and compatibility are a concern have a look out for another Spesh frame in your size, they come up all the time, I managed to swap everything off the rockhopper onto an Epic without too much trouble.

Brilliant tips guys, ta very much.
I'll keep a look out for a 19" rockhopper frame as that would probably be easiest and cheapest as I like my current bike, just a pity its a bit big.

In the mean time I'll measure up my current bike for an upgrade. If i get a good frame I can then slowly upgrade until I have a real good set up.
Decisions decisions….

I rode a bike that was too big for ages when I got back into bikes (a 21" '99 rockhopper as it happens) then bought a nice 2nd hand 18" frame. It made a world of difference. You're really limiting your enjoyment of cycling by riding an ill fitting bike. which is a shame.