What size are your tires, post the size on the sidewall please.
1) Consider changing to 700c (622mm) wheels. That will give you a huge selection of wheels & tires compared to 27" (630mm). You need to be able to adjust your brake pads 4mm "in" or towards the ground, 6-8mm is better. This lets your pads brake the smaller diameter wheels.
2) Your rear drop out spacing (O.L.D.) is probably 126mm, so you would look for 130mm spacing on a 700c wheel. The frame should easily widen 2mm each side.
With 700c wheelsets you'll have a huge selection of alloy rims. I would suggest changing the rear gear cluster to a cassette from the freewheel you have.
I had a dog that weighed as much as you, so you could go to a 32 spoke rear & still be pretty safe with bumps. If you're a gambler you could go with less, but it's a risk. The front wheel isn't quite as important, if you have a death wish you could go 28 or less.
When you see a bump you have to be "light on the bike" so the wheels don't take the shock.
You may end up with rims drilled for presta valves, no big deal.
Aluminum rims will help you accelerate faster, but are not going to do anything for you cruising speed on the level. The faster acceleration will reduce your travel time, especially in an urban environment.
What is your budget? Are you comfortable truing wheels yourself?
Nigel
Aluminum is only stronger than steel if its a forged piece, a cast one is junk and unfortunately thats what most wheels are out there. For my money on a trail rig, steel is a much better choice. I like the ability to beat and weld on it if I wanna add something easy, and I like the extra weight down low.
(03-26-2015, 02:29 PM)DaveM Wrote: (03-26-2015, 01:01 AM)eastman Wrote: Aluminum is only stronger than steel if its a forged piece, a cast one is junk and unfortunately thats what most wheels are out there. For my money on a trail rig, steel is a much better choice. I like the ability to beat and weld on it if I wanna add something easy, and I like the extra weight down low.
I would stay with your steel wheels, especially if they have a nice chrome finish. If you change to aluminium I suspect you will have no trouble selling the steel pair of wheels.
I've literally never heard of a bike rim being made from cast aluminum. Maybe you're thinking of auto rims? Also not sure exactly what you would want to "add" to a bike rim by welding, but OK.
To the OP. Aluminum rims will be lighter, less likely to bend (if they're built properly) and brake much better than steel rims. That being said, new wheels are a pretty big purchase if there's no problem with your current wheels. Me general advice is usually get good tires and brake pads. Replace other things only as needed.
"Where ever we go, there we are"