Opinions on rim locks

[DustyDave]

Welp I spun the The Scout's rear tire (4.00x18 K81) on the rim again yesterday, Pulled out on the highway and just barely lifted the front wheel and by the time I hit high gear I had a sudden flat. this it the third valve stem I've pulled out of a tube in the last couple of years. I keep increasing the air pressure thinking that will stop it. It had 30 pounds in it yesterday, so I guess whether I want to drill a very nice 79 year old rim or not it's going to happen. Any suggestions on good rim locks I have seen 4 holes on each side and wood screws into the bead but don't know how that will work with kinda modern tires.
Dusty

[hillcat]

Damn DD, I haven't seen the four screws trick in many years. Used to have it on some of my dirt bikes as a kid (Montessa 360, Bultaco 250)
Are you sure they still do that? Seems like last resort.
Maybe try one of these. https://www.rockymountainatvmc.com/t...pro-rim-lock-p

[farmall]

The classic style hillcat posted work very well. Typical installations use two, 180 degrees apart. Put some anti-seize or dielectric grease on the threads. You'll want to balance the wheel afterwards.

[MOTher]

If you do use screws: Harley used #10 x 3/8 screws in aluminum rims, so they didn't go very deep into the bead, not enough to damage the cord of it. You can also tell an original Harley factory drilled rim from one done by someone else as HD's have a small flat, counter bored for the head of the screw, while most others forgo that step. I'm about to screw a rim for my Sportster, and I'll take the time to to counter bore a flat for the head. I also plan to use 5 screws on a side rather than 4 for aesthetic reasons. 4 just seems visually "square."

BTW I absolutely hate fixing flats and mounting and dismounting tires with the style of rim lock in Hillcat's post.

[MOTher]

Here's a quick paragraph from an older, '57 to '69 Sportster, Harley factory service manual: "Steel rear wheel rims should be barbed. If not add barbs to inner wall of bead using a cold chisel. Locate the barbs in three groups, one group symmetrical about the valve stem hole and two additional groups located approximately 120° either way from valve stem hole as shown in Fig, 2C-19B. Each group should include 16 barbs, 8 barbs to a side, with 4 barbs facing opposite the other four. Barbs should extend approximately 1/32 in. to 1/16 in. in height from surface of rim."

Not in the Harley FSM: Watch out for these barbs when you mount or dismount a tire, or replace a tube. It's almost a guarantee you'll catch a finger or two on one or more of them.

[farmall]

I'm wondering if the problem is specifically due to the relationship between the K81 bead and that particular rim.

I've only used K81s on Britbikes and never needed to compare bead designs but presumably the original bead contour wasn't prone to slipping on the original rim. Some anti-skid paint down the bead seat area would add traction and protect the inside of the rim from corrosion.

BTW I don't run the valve stem nuts all the way down on tubes so if a tire starts slipping ya can see the stem tilt instead of having it tear from the rubber. I let 'em float about 1/2" away from the rim. The nuts are assembly aids more than anything else.

[Dougtheinternetannoyance123]

It depends on the bike, specifically for Brit Iron, ALL the dual sport models, IE: TR6C, T100C, TR5, and anything that might or might not go off road came stock with the funky & PIA rim clamps. Many Nortons both street bike and off road do as well on the rears. Same with AJS/Matchless scramblers. However this debate comes up often and I heard many dire and frightening tales so the consensus seems to be split from Alfred E Nuemans "What me worry?" and those promising blood and mayhem if you dont use them.
Personally, Only time I had an issue on a street bike was, frighteningly my wife on the freeway, And she got it off the side of the road on the way to a run. Keep in mind, the old school method of suspension on choppers was to run the rear tires underinflated for some extra cushion. I HAVE seen a lot of alloy compy model rims with some pretty extreme serrations around the edge of the rim, and more than a few with rim screws.

[farmall]

OPs rim is apparently an Indian part since it's so old. I'm not at all familiar with Indian rim internal contour.

I don't run rim locks on street bikes but I don't run low tire pressures. I've never had a valve stem tear off.

[Luky]

Many brands of modern tires ARE harder if not impossible to change with hand tools. The tires fit much tighter now.
One trick to keeping from tearing valve stems is to NOT put the nuts on them, on the outside of the rim. That way they may get on a angle but not tear. It allows some movement.
Many racers learned that the CORRECT tire pressure WAS 30 lbs. if you wanted to win races. NOT 16-18 lbs. as suggested by track side know it alls.

Go ask the people that win races what tire pressure should be. That is how I started winning races.
When I asked the winners what they did to their engines they said they did not change anything.
They just followed the manufacturers recommendations.

[farmall]

K81 was "modern" with respect to 1930s/40s US rims but is very far from modern now.

I don't change many tires but an independent shop might know which suck the most to break loose for a given rim size. That suckage could be put to good use to avoid drilling an ancient rim.

[DustyDave]

Well I spun it again and I know that I didn't lift the front wheel and it had 40 lbs. So I took it all the way off the rim and inspected carefully. The bead is covered in flaking rubber almost feels like graphite This got me worried so I broke the front that was bought and installed at the same time and it was stuck hard and the rubber seemed normal. So I ordered a new K81 then wire brushed the bead to a slightly better surface and put 8 wood screws in it so I could make the Dennis Hopper memorial ride Saturday, only about 150 miles and I rode very conservatively. Never saw a tire do this before and certainly hope it's a one off. Would have preferred the rim locks but I really hate to tell everybody that I'm going to be there and not. Been really abusing it since I got home just to see, but the new one goes on the day it gets here.
Dusty