calstar

Whats the weight difference between a 80s Japanese production fork made of cromoly vs hi-ten? Given the same butted frame mtl would the difference of a hi-ten or a cromo fork be noticeable(significant or otherwise)? Bike is a Bridgestone T500, cromo butted frame but has a hi-ten fork.

thanks, Brian

old's'cool

I don't have apples-to-apples for you but here's what I have:

1. Fork #1, Reynolds 531, weight 1.8#
2. Fork #2, Hi-Ten, approximately same steerer length, weight 2.0#

This was on a digital bathroom scale, measurements repeated several times, mode value for each fork selected.
I did not do a measurement systems analysis, so my rough assessment of the measurement error is +/-0.2#. That is also the resolution of the scale.
All that said, the 531 fork appears to be about 0.2# or 10% lighter than the Hi-Ten fork. I'm pretty sure it isn't heavier, and also pretty sure it isn't more than 0.4# lighter than the Hi-Ten Fork.

3speedslow

Don't focus on weight between the two, think ride quality. A better fork material is going to give you a better ride. It's a lot like tires too.

uncle uncle

Others can chime in here, but if I remember my Strengths of Materials classwork correctly, chromoly steel is going to be about 1/3 less in weight, for the same strength, as "hi-tensile" steel. So, in a perfect world that's the maximum you could expect to save over the weight of your existing fork. Whether that kind of weight savings is significant is purely up to you and your belief in what "significant" means. Old's'cools weight numbers are probably closer to what the actual weight reductions are in the real world. Production manufacturing methods don't allow fork wall thicknesses that vary along the length of the fork blades to produce thicknesses narrowed in the areas where forces are less and the extra material is unnecessary for the loads it would see.

Chris Chicago

I would bet that in a blind test very few people could notice a difference in ride quality.

randyjawa 

Exactly!

phoebeisis

I compulsively weigh "stuff" bicycle motorcycle car truck
That number old and cools-10% -pretty good
If you go fancier-more expensive 853- you might get another .1lbs -5%-at best.
And gotta agree-I couldn't tell the difference between ANY fork material(maybe CF VS heaviest crude steel-maybe)
Maybe folks on BIG framed bikes-I'm short 20" road 14" mtb- differences in frame material ride quality is more obvious(taking edge off sharp bumps)
But shorter small frames-shorter tubes-tough to tell them apart.

Tires volume pressure-have much much much more effect on ride quality-taking the edge off bumps-
Now light bikes are nicer because lighter components are usually better made prettier easier to work on.
Lighter bikes are Easier for oldsters to out on racks haul around the house- 26lbs vs 30 lbs(mtb style)-matters as you get older.
Charlie

calstar

Thanks for all the replies. You all confirmed what I was thinking, just wanted to check in here and tap the wealth of accumulated knowledge. BTW this bike is being built for a friend who is getting back into riding after about a 30yr lay off, I'm sure he won't be dissapointed with the ride.

Brian

cycle_maven

Framebuilders often used hi-ten fork blades and stays so they would be easier to bend to the right offset. Chrome-moly is a beotch to cold-set. Plus chro-mo is more flexible when you make thinner tubes to take advantage of the stronger material. And "flexible" isn't a word that I like to hear when applied to my forks. Plus it only saves a couple of ounces.

mctrek

I have an 85 Trek 400 with Hi-Ten Steel fork and a newer 89 Trek 420 with chrome-moly fork. Same size and I can not tell any difference in ride quality. My 2 cents.

ksisler

Basically Hi-tensile fork is the one you don't want and chromo fork is the one you do want. As they are going to cost about the same in the open market, why not buy the lighter/stronger/safer/more resilient chromo one?

PM if you need sourcing help for the forks...but they are pretty easy to find on ebay or amazon or bike specific sites.

/K

fietsbob

Lower yield mild steel , use more, higher strength , chromo, 531, 753, etc. allows less material ,
same strength.

China fork, labor to build it costs less , hand made in Western Shop, costs more.

David Newton

My "rider" is a Bridgestone 300 with the same combination as the 500. The 500 has double butted main tubes, the 300 straight gauge Chromo.
I've been riding it daily for several years, and the forks are resilent over street roughness. A comfortable ride.
Maybe a butted Chromo fork would be more resilent, but I doubt I could tell the difference.

zukahn1

As for weight on vintage Japanese forks cro-mos are about 1.8 lbs and hi-tens are 2lbs and magnalites are about 1.6. There is very little if any noticiable difference in ride quality and strength is about the same for all. So if your looking for a fork just go with one that is a good match fit for the bike.

old's'cool

I couldn't disagree less!
My qualitative analysis of the fork's effect on ride quality is that it will depend alot on the net rake, i.e. the horizontal distance between the front wheel axle and the bottom of the steerer, and also a lot on the stiffness of the crown and the bottom of the steerer, since that's where the moment arm from vertical loads and hence bending forces are the highest. I know it's not pleasant to think about the bottom of the steerer flexing, but I'll bet it does alot on large vertical impacts.

Hudson308 

Fork from my 61cm '83 LeTour Luxe (CroMo?) weighs 2.07 lbs. on a postal scale with no bottom race. Fork from my 61cm '79 World Sport (Hi Ten?) under same conditions weighs 2.05 lbs. Scooper has listed the weight of his 61cm '73 Super Sport (CroMo?) fork with no race as 1.96 lbs.

noglider 

Chro-mo has a better strength-to-weight ratio. This makes it possible to reduce the amount of material to make it lighter without sacrificing strength. Just because it's possible doesn't mean the maker has done it. Some chro-mo stuff is as heavy as the cheap stuff, so the only benefit is that it's more crash-worthy, to which I ask, so what? Two forks of the same weight and dimensions will ride THE SAME.

noglider 

Also, all forms of steel alloy have the same stiffness. Some people are under the impression that the high end alloys are stiffer than the cheap stuff, but metallurgists tell us this is not at all true.