Conference noted::bicycle

	RE: .0

	I recently built an aero tubular front wheel for time trials
	and Triathlons.	I was concerned with the strength of the wheel 
	since at 190 lb(and dropping) I don't want the wheel to fail 
	while I am sprinting or on a fast decent. 
	
		HUB:	American Classic 28 hole
		SPOKES: Hoshi Bladed. Radially spoked
		RIM: 	Mavic Iso - 345 gms, 18 mm
		TIRE: 	Panaracer Ultima - 150 gm, 17 mm, 130 psi

	I have about 200 miles on this wheel with no problems other
	than hitting a pothole at 35+ mph and flatting. 

	I originally wanted the Wolber Aero rim (don't know the weight 
	off hand) but the shop was having problems finding one. I chose
	the Matrix over the Arya because the Ayra has a heavy seam.

	Paul

    I thought I'd elaborate, I considering:
    
    	Matrix ISO	- 345 g, 18 mm
    	Sun Mistral 19A	- 310 g, 19 mm
    	Araya ADX-4	- 325 g, 19 mm
    
    So far, the Matrix is the leader in terms of price. Anyone know about
    the relative durability of these rims? 
    
    I'm also considering DT oval or Performance aero spokes for the front
    wheel, cross 2.
     

    I have built two pair of wheels using Campy Record hubs and Araya ADX4
    tubies with hooked bladed spokes, 3X rear, 2X front.  One was 28 hole,
    the other 32.  They were great.
    
    After my crash in Capron, a mechanic "trued" the rear 28 and it started
    to wobble after 150 miles or so.  I think it's because the mech. was
    not too good (from other observations).  I later retrued it and it
    seems fine.
    
    They whistle but that's the blades not the rims.  I only use tubies
    when I'm within a reasonable distance of "home" or "support."
    
    ed

    Be careful with hooked (like Hoshi) spokes spoked radially.  
    A friend spoked radially with Performance 15 ga. hooked, bladed
    spokes (Hoshi are 14 ga.) and had trouble with them pulling through.
    He changed to Wheelsmith diamond shaped spokes, headed but able to
    pass through a 14 ga. hub hole and eliminated problems on a front
    wheel.  He had also used the Performance blades on the rear wheel
    and after some miles--about 200--they were looking a little strained
    so the wheel was rebuilt with Hoshi blades cross-three and has worked
    fine for about 400 miles now.  It appears that the crossing patterns
    keep the pull at the hub hole better aligned with the hook in the spoke
    than radial, at least to radial with spokes on the inside of the hub flange.
    
    I am running 32 spoke cross-three built iso matrix wheels with Hoshi
    blades in both wheels and have not had any problems with spokes for
    a 200 pound rider.

    I decided to go the more conservative route, to start, with the spoking
    patterns. For the front, 2x DT 15/16/15 gauge, and for the rear, 2x DT
    15 gauge (plain). This should be fine for my weight (140+ lbs.).
    
    I found some Araya rims and weighed them: they're around 340 g., a
    little more than the advertised 325 g., but they should do. I got them
    for a good price, otherwise, I would have gone with the Mistral 19A at
    310 g. I took the plunge with the hubs and got the Dura-ace 7-spd.
    cassette with a slotted front (this feature I'll make use of if I ever
    want a TT-only wheel). Finally, the tires: I read in Velo-news that the
    tires (the leading edge) should be wider than the rim. The 22 mm
    Vitorrias I had been curing in my cellar should do fine with the 19 mm
    Araya rim.
    
    I was thinking of doing some comparison testing by timing descents with
    the different wheels -- has anyone done anything like this? I thought
    I'd time a descent from a running start of say, 15 m.p.h. with no
    rider-applied power for several runs with each set of wheels. I'd use
    the cateye to record to time, average speed, at top speed - all factors
    which are likely to vary. If I get around to this, I'll report it here.
    
    Roger

< Note 1279.5 by TOOK::R_WOODBURY "why silver bullets!?!? ..." >
                    -< Giving Araya + Dura-ACE + DT a try >-

>    I decided to go the more conservative route, to start, with the spoking
>    patterns. For the front, 2x DT 15/16/15 gauge, and for the rear, 2x DT
>    15 gauge (plain). This should be fine for my weight (140+ lbs.).
    
>    310 g. I took the plunge with the hubs and got the Dura-ace 7-spd.
>    cassette with a slotted front (this feature I'll make use of if I ever
>    want a TT-only wheel). Finally, the tires: I read in Velo-news that the

I seem to remember reading somewhere that you shouldn't rebuild a wheel with 
the same hub and a different spoke lacing pattern.  Something about stressing 
the spoke holes in the hub leading to breakage.

>    I was thinking of doing some comparison testing by timing descents with
>    the different wheels -- has anyone done anything like this? I thought
>    I'd time a descent from a running start of say, 15 m.p.h. with no
>    rider-applied power for several runs with each set of wheels. I'd use
>    the cateye to record to time, average speed, at top speed - all factors
>    which are likely to vary. If I get around to this, I'll report it here.
    
I've done this sort of test to determine optimal aero bar adjustment.  However 
I started from 0 (on the side of the hill) and just did a glide-down until I 
stopped and marked all the stopping points.  Since the cateye Micro (if that's 
what you're using) only measures mph in whole numbers, you may find it hard to 
be precisely 15mph (or whatever) for your running start.  Using the same 
cadence might be more accurate, tho changing wind conditions could affect your 
speed as well.  Top speed is also recorded in whole numbers, so you may not 
see any change.  Assuming that the Cateye doesn't round but just records the 
whole number part of your speed, one run could measure 30.01 and another 30.99 
and you wouldn't see any difference in the max speed readout.

If you really want to do this right, use the protocol the downhill speed 
skiers use... at the steepest part of the hill (or somewhere near the bottom 
where you think you'll hit max speed) set up two marks some reasonable 
distance apart and have someone else time you thru these 'traps'.  Don't do it 
yourself... any movement on your part could affect your speed.

Where would you be doing this?  A few friends of mine would like to test disks 
and disk covers this way, and we all could use some help.  Could be fun.

Kevin

  	re: .5

	I had always heard the tires had to be narrower that the Rim. 

	I would think twice about the 2x in the rear. When you go with
	a spoke angle that is less tangential to the hub you get more 
	hub wind-up which causes a lot more stress on the spokes. Try a 
	3x on the freewheel side and a radial on the other side. This 
	will make for a stronger wheel. 

	Paul

    re. -1
>where you think you'll hit max speed) set up two marks some reasonable 
>distance apart and have someone else time you thru these 'traps'.  Don't do it 
>yourself... any movement on your part could affect your speed.
>Where would you be doing this?  A few friends of mine would like to test disks 
>and disk covers this way, and we all could use some help.  Could be fun.
    
    	What you could do is to contact the local Fish and Game Club
    (One on Tinker Road if your in Nashua) and ask if one of the members
    would let you borrow a speed trap that they use for clocking different
    loads and weights of bullets.  They basically start and stop by
    breaking a fine wire on each device.  This wire (celophane) could be
    across a section of the road and the wheel would start and stop the
    clock similar to a bullet.  Guranteed accurate to .00001 mph.
    
    						_Jerry
    

Steve Hed's concluded from his windtunnel tests that objects should be 
streamlined with an airfoil-type shape it's length/width ratio of 3-to-1.
In order to do this the tires need to extend over the rim by 1mm on each side.
He goes as far as to tell you to measure the tires, and not to go by the
manufacturer's claimed width.  This sounds a little extreme to me.
He estimates an improvement of :01 per mile at 30mph.  The Kestrel downtube 
happens to have this shape as well.  

I'm not sure that the wider tire theorywould apply to a disk wheel.

JD