Mountain bike upgrade

[vRS_Pagey]

I am looking to upgrade and hybridize an old Carrera Furnace, when I say old, iirc it was bought in the late 90's.  Despite the age it is still a very good bike.  So far I have changed out the shifters and switched the old cantilever brakes for V type, I've added semi-slick tyres which make a massive difference on the road.  The next step is to add suspension forks, the current diameter is a standard 1 1/8.  I got a new set of forks but really struggled to fit them, I was wondering if I should a new headset for it to work?

Any advice would be appreciated.

[Tortaruga]

The old headset cups are most likely knackered (they'll be all pitted) so it'd be a good idea to replace it anyway. Hope make brilliant headsets and they're a British firm too. Expensive though - try and get one on Ebay 2nd hand.

What exactly was the struggle to fit the forks? If the steerer diameter is 1 1/8" it will fit-doesn't matter about a new/old headset. I think something else might be wrong or your fitting method is not right.

[vRS_Pagey]

The old headset cups are most likely knackered (they'll be all pitted) so it'd be a good idea to replace it anyway. Hope make brilliant headsets and they're a British firm too. Expensive though - try and get one on Ebay 2nd hand.

What exactly was the struggle to fit the forks? If the steerer diameter is 1 1/8" it will fit-doesn't matter about a new/old headset. I think something else might be wrong or your fitting method is not right.

Probably the latter mate, the new fork just wouldn't sit correct in the stem even when everything was fitted and the handle bars on the forks rocked in the stem!!  I was almost like the geometry was wrong, after trying to refit the old forks I had the same problem though so headset knackered me thinks.

[Tortaruga]

You know that the steerer needs to be cut to the correct length (it should sit 2-3mm below the top of the stem).This allows the correct compression on the bearings so the fork won't rock. It needs to be cut with a proper tube cutter too, not a hacksaw!

[vRS_Pagey]

Yeah, the steering tube needed about 50mm removed but it was only a dry fit to get the exact height, luckily I didn't cut it as I discovered the lockout on the forks was faulty, so they've been returned today!!  I was going to use a pipe cutter from my plumbing kit?

[Tortaruga]

I was going to use a pipe cutter from my plumbing kit?

That will work perfectly.

Your OP seems to indicate that you'll be using the bike on the road. Now that you've returned those forks I'd suggest getting rigid carbon legged forks - light and maintenance free.