ed 

These are the stanchions on the Tora 289 and 302. I'm perusing my options for a new Crapper fork.



I don't know much about this metal composition stuff, but I'm juggling a 302 vs. 318 sorta thing. Since it's the Crapper, Motion Control isn't crucial, but at least a turnkey lockout would be beneficial.

Mmmmm...how 'bout some nice teal:
1. Scope

This Korea Industrial Standard specifies the carbon steel tubes, hereinafter referred to as the "tubes", used for machinery, automobiles, bicycles, furniture, appliances and other machine parts.
Remark
1. The units and numerical values given in { }in this Standard are based on the International System of Units (SI) and are appended for informatibe reference.


2. Grade and Designation
The grade and designation of the tube shall be as given in Table 1.
The subclassification letter symbols A, B and C are used to indicate distinction of method of manufacturing the tube, cold working process, heat treatment, etc.


3. Method of Manufacture
3.1 The tubes of Grades 11, 12 and 13 shall be manufactured by seamless process, electric resistance welding process, or butt welding process, and those of other grades shall be manufactured by seamless process or electric resistance welding process.
3.2 The tube shall be as manufactured or as cold-finished condition, or they shall be subjected to appropriate heat treatment.

4.Chemical Composition

5. Mechanical Properties

6. Apperance
6.1 The tubes shall be practically straight. and the two ends shall be at right angles to the axis of the tube.
6.2 The tubes shall be free from defects detrimental to pactical use.
6.3 The surface finish of the tubes, when especially specified shall be agreed upon by the purchaser and the manufacturer.

7. Dimensional Tolerances

8. Test

9. Inspection

10. Reinspection
The tube may be retested in accordance with 4.4 in KS D 0001.

11.Marking
Each tube having passed the inspection shall be legibly marked with the following items, the order of arranging the items is not specified.
However, for smaller tubes or on a request from the purchaser, tubes may be bundled together and marked for each bundle by suitable means.
(1) Designation of grade
(2) Letter symbol indicating the manufacturing process(¹)

Note (1)
The letter symbol indicating the manufacturing process shall be as follows.
However, the sign may be replaced by a blank

Hot finished seamless steel tube -S-H

Cold finished seamless steel tube -S-C

Electric resistance welded steel tube other -E-G
than hot finished or cold finished ones

Hot finished electric resistance welded steel tube -E-H

Cold finished electric resistance welded steel tube -B

Cold finished butt-welded steel tube -B-C

12. Report
The manufacturer shall, as a rule, submit to the purchaser a report on the test results,manufacturing process, ordered dimensions, quantity and work lot number traceable to the history of manufacture, etc.

dminor 

What did you do, just copy and paste the first Google hit you got?

STKM appears to be an Asian standard of hardness and modulus e for drawn seamless internally honed chromoly tubing, often chrome-plated on the outside. They are the Asian counterpart to JIS standards. It can be hot or cold-drawn tubing, although I'm assuming that the cold-drawn is going to be the higher stengths numbers.

Really, the numbers are the crux of it. Saying it's STKM steel means nothing without its attendant number to tell you what it really is. The way SRAM is bandying the term about, it's like it's some special metal, when really it's a standard.

We really need Falanx, our resident materials scientist, to weigh in on this one. Wonder if he still lurks about?

ed 

Should I just crap on the idea and go for the 4130 on the 318 then? I don't suppose I'm going to be abusing an 11 y.o. frame all that much. Just singletrack.

Metzinger

Materials science debate on a Tora?
Are you sure you wouldn't be better off with a rigid fork and a bigger front tire?

ed 

I actually have the Rigid Raleigh Pointe with a 2.7" front tire already. Crap bike, but it works. I would much rather have a couple lbs of dampable dead weight with 3-4" of travel than 1.5-2lbs of bouncy rotating weight. I run the 2.7 around 15psi, hahaha.


I liked my Tora. It was the first year for it, so it was called the Tora Solo SL or something like that.

dminor 

If you only need 4" and want lateral stiffness, I have a sweet little dual-crown Judy XLC I'd let go of

ed 

Tempting...but I wouldn't be able to do those "xc barspins" anymore.