Is a Pedal Torque Wrench (15mm) needed for initial assembly (RR6+ST)?

[ykanti]

I read the thread "did you use a torque wrench to assemble your bike" with interest and have purchased a 1/4 inch torque wrench set to assemble my RR6+ST soon.  For the pedals, the instructions (video) say to tighten to exactly 35 nm using a 15mm wrench.  I don't expect to change pedals often and there's a bike cooperative near me (1.5 miles) that allows people to come in and use tools there.  Is it an OK idea to tighten the pedals at assembly time without a torque wrench ("snugly") and head (ride) to the co-op to borrow a pedal torque wrench to get the "exact" torque before riding extensively??  The warning on the video suggests some combo of plague, death, dismemberment and/or general unhappiness may occur if 35 nm of torque is not precisely achieved ;-). Thanks in advance for your advice.

[handlebar]

The warning on the video suggests some combo of plague, death, dismemberment and/or general unhappiness may occur if 35 nm of torque is not precisely achieved ;-). Thanks in advance for your advice.

Always glad to provide advice even if I don't know what I'm talking about. I imagine the vast majority of pedals are tightened by feel, and loosening doesn't seem to be a problem. The left-hand threads on the left pedal help prevent loosening. That was one of James Starley's innovations when he invented the first useful bicycle.

American bicycles didn't have that feature in the 19th Century. Perhaps it was due to fear of litigation by Albert Pope, the robber baron who took over something like 74 of the largest American bicycle manufacturers. A crank from the Wright Brothers' shop has been found to have left-handed threads on the left. They must have been unaware of it because their catalogue indicated that American pedals would fit. Any patent would have expired; so they would have bragged about the feature if they'd known. To me, that's solid evidence that they were dealing in parts smuggled through Toronto. It appears to me that their business was far bigger than their records show.

Recorded American bicycle sales dropped 80% from 1900 to 1905, but the popularity of bicycling seemed to be growing. I think most sales went unrecorded because dealers like the Wrights wished to avoid scrutiny as they drove Pope and other barons out of the business.

[handlebar]

For the pedals, the instructions (video) say to tighten to exactly 35 nm using a 15mm wrench. 

I watched the video. I liked the part where they said to photograph how it's packed. I don't recall any such instruction for my Radrunner a couple of years ago.  I came to regret not doing it when I unpacked my Six Three Zero last summer. They seem to keep costs down by using a lot of factory reject parts, and it seems they count on customers being unable to repack the junk to send back. My Radmission, a similar bike, came in a box 12" deep, but the Six Three Zero box was only 8" deep, and they said they would reject a return in a box that did not match its dimensions. Repacking was a grueling task that took me 11 days. Part of the trouble was trying to find out how to get the front wheel and handlebars into a box only as deep as the length of the crank.

It looks as if the mechanic in the video tightened by feel, without a torque wrench. The torque specification sounds like lawyer talk. Out of a million consumers, some might not use a wrench, meet resistance with only a couple of threads engaged, and stop. Under a rider's weight, it could break loose, damaging the threads and perhaps injuring him. Now their lawyer can say it was the consumer's fault for not following directions.

The included 15mm wrench is 5" long. 35 newton meters would require 62 pounds on the other end. I have a 15mm combination wrench that's 7" long. It would require 44 pounds. That's more reasonable. Either way, you'll probably get it tight enough even if it's not nearly 35 newton meters. Lawyers!!!

A wrench made for a certain size connector will probably give suitable torque with reasonable pressure. A ratchet handle big enough to tighten a 3/4" fastener, could easily overtighten a 3/8" one. One morning in 1983 I replaced the water pump on my grandmother's Wildcat. My uncle was there. He'd helped install the engine 19 years earlier. As I tightened the 7/16" nuts with a 3/8" ratchet, he advised me that I was overtorquing, and I realized I was pulling too hard for nuts that size. Now I knew why the Air Force had kept him 35 years. He was sharp!

If I'd been paying better attention, I would have stopped when the fastener's stretch stiffened. I think a torque wrench usually isn't necessary, but it can prevent mistakes like that.

[handlebar]

  For the pedals, the instructions (video) say to tighten to exactly 35 nm using a 15mm wrench. 

https://amzn.to/3yYQrc8

This seems to be the pedal wrench in the video. There doesn't seem to be such a thing as a torque wrench for pedals. Maybe I'll order a fisherman's scale. I can convert newton meters to pounds on a certain size wrench and pull on the wrench with the scale. I'll make an instructional video and sell it to Radpower for big bucks!

[DuaneL]

though if you want to use a torque wrench you can use a Pedal Wrench Crow Foot and a torque wrench (a bigger 1 then you would use for most other things on the bike except wheel bolt) set to 26 ft lb and for the right pedal have the torque wrench facing the opposite way then normal (where the drive is facing you so that the torque wrench thinks it is tightening not loosening if you wrench is like mine and only clicks for tightening)

[Muskie1]

 I rebuilt motorcycle and hi po csonarengines for a long time. After working in   a car dealership for 40 years as a salesperson  knew all the mechanics. All went by feel.

[Eric7]

I think you can buy a cheap one mail order.  I have a pedal wrench from Park.

It is one of those luxury items you think you don't need. But then it is nice to have.  I have a few pedals and I can switch.