Mountain Biking - newbie: aluminum vs. steel

Hello,

Just wondering if you could answer a question about a purchase I was thinking about making. I am interested in two bikes, a Trek 820 (steel frame) and a Trek 3700 (aluminum frame) Which of the two would you recomend? From what I've read they are essentialy the same bike, the only difference being the frames. I understand the steel frames are very ruged and give a smooth ride although obviously the alumininum is lighter. For the way I'm planning to ride (mostly smooth trails, 30 miles or less) which do you prefer for the price? Considering that I am trying to stay within my budget, do you see one as being better than the other? I like the ride and durability of the cheeper steel model, but do you see the extra $60 worth it for the aluminum? Also, in your opinion is the lighter aluminum better for going longer distances? That is to say, can you pedal it easier with less fatigue at higher speed over longer distances? Any information you can provide is most appreciated.

I think the decision comes down to a test ride. Ride them both, and go with the one you like best.

Steel is considered to be more forgiving than aluminum, the frame has more flex, thus transfering less of the vibrations to your body. Conversely aluminun feels more rigid and some say it responds better.

Steel can be bent and reshaped, so if you bend dropouts, a steel frame has a better chance of being fixed. With aluminum, you need replaceable dropouts, so that they bend not the frame.

With steel you may have issues with rust, if the bike gets dings and such. This is less of an issue with aluminum.

Hope this helps.

Steel is considered to be more forgiving than aluminum, the frame has more flex, thus transfering less of the vibrations to your body. Conversely aluminun feels more rigid and some say it responds better.

Are you sure about that? Steel is a LOT stronger and much more rigid than aluminum.

General rule of thumb is a steel frame is more forgiving. Aluminum when built on a fr ht is usually VERY stiff. You are thinking of thickness vs thickness. With how most frames are welded the steel bikes feel less harsh.

The idea goes like this...

Steel can flex much more than aluminum and not break. This assumes equal dimension samples of each. Aluminum is lighter. To make up for aluminum’s inability to flex, manufactures tend to use more material to achieve the same strength and still have a lighter product. This can make a bike frame stiffer.

I personal will only ride steel frames unless it is full suspension. My back can't handle a stiff aluminum frame.

Thanx. I was trying to explain that but was busy at work and couldn't word it right. Cheers

Ok guys I just need to point out that we aren't dealing with good steel here. This isn't an 853, 631 or even a 4130 bike. Heck its not even cromoly!

This is a "High tensile steel w/Cro-Moly seat tube" (straight from Trek)

Huffy uses Hi-Ten steel... its extremely low grade. I am 99% sure the frame is not butted, meaning heavy straight gauge tubing that will negate any dampening effect the steel may have. It would be worlds different if we were talking about a DeKerf, On-One, Gunnar, Jamis, Kona, or any other manufacturer with a good steel frame, but this isn't going to have that "steel ride quality".

Hehehe...oops. Didn't read the bikes he was looking at. I was just going by generics when it comes to average and above bikes.

Hey seely, not to argue, but what grade alloy is on the 3700? I'm guessing that the ride characteristics will probably be about the same. Weight will also be about the same.

I'd recommend the steel and then if you really get into this sport you should get a decent 2nd bike when the time comes.

Take them money you save and buy a helmet and some gloves.

L8R

Hey seely, not to argue, but what grade alloy is on the 3700? I'm guessing that the ride characteristics will probably be about the same. Weight will also be about the same.

I'd recommend the steel and then if you really get into this sport you should get a decent 2nd bike when the time comes.

Take them money you save and buy a helmet and some gloves.

L8R

My entire point is that the 3700 will ride the same as the 820 given they are both lower grade frames. The 3700 is lighter, therefore since ride quality is a moot (word of the day) issue why not get the lighter bike?

My entire point is that the 3700 will ride the same as the 820 given they are both lower grade frames. The 3700 is lighter, therefore since ride quality is a moot (word of the day) issue why not get the lighter bike?

I agree 100%! The question is, "Which one IS the lighter bike?".

I'm not too familiar with either, but I know that lower end aluminum can be just as heavy as cheap steel. Does anyone know the "actual" weight of the the two models in question?

If the 3700 is lighter, by all means it's the better choice. If it's the same, save your money and stick with steel.

L8R

The difference between the 2 frames when they were put on the scale was about 4 lbs. My question is, how much difference does 4 lbs really make in terms of riding up hills and doing distance rides? Thx, all info is most appreciated.

4 lbs is pretty significant for a bike. Assuming all the components are the same, that's a HUGE difference.

Now, when trying to "cut" weight off a bike, the best place to do so is the "rotational" mass. i.e, the wheels.

A heavier bike is simply more resistance when climbing or even pedaling on flat ground. The benefit, it'll make you a stronger rider.

L8R

The difference between the 2 frames when they were put on the scale was about 4 lbs. My question is, how much difference does 4 lbs really make in terms of riding up hills and doing distance rides? Thx, all info is most appreciated.

4lbs on a bike is fairly significant. When you are looking at a $550 bike vs. a $1800 bike, the difference between the two is about 4lbs, so its enough to make people pay the big bucks.

Anyways where you notice weight the most on hills though, is not in the frame, but in the wheels and tires. I had a heavy wheelset once, designed for abusive riding, and I HATED it on the hills. The weight difference between the new wheels and my old set was maybe a pound, but it felt like 20lbs. Now that being said, if all the weight difference is in the frame you won't feel it as much. I've heard it said every 5lbs off the bike is worth 1lbs off the wheel, meaning you get much more from a lighter wheelset in terms of performance.

That being said, if you get the 820 and loose 4lbs riding it, you will have a bike thats the same weight as the 3700 :p

2 Bikes. Bianchi aluminium and an old Kona Explosif in steel. Both have their own different rides, but If for comfort, I ride the Kona, but to make hills and rutted single track with ease, it has to be the Bianchi. Both are quality bikes with quality butted tubing, but If you compare like for like, Aluminium will be stiffer, ideal for climbs and no loss of power through flexing, wheras steel is more forgiving on the body. Incidentally, both bikes weigh within 1lb of each other , Kona at 24.5 lbs and the Bianchi at 23.6 lbs, both are hardtails, and both have the same wheelsets. Mavic 517's on XT hubs, and generraly run the same tyres.

to make up for that 4lb difference would probably mean new wheels and new bars/stem/post/cranks... i'd go with the lighter bike