Why don't new pedals fit my old Raleigh?



C

Chip C

Guest
I've read prior threads in this group that seem to indicate that
9/16"x20 pedal threads are really very standard, yet I still find that
generic new pedals don't fit my old (probably mid-'70's) Raleigh
Sports. They get about a half-turn in and that's it. I have three old
sets of pedals (in five years I've broken three pedals, all on the same
side; what's up with that?), two of them Raleigh-branded and one
unbranded but "for Raleigh", and they all thread in very easily.

They're all visibly the same diameter and all 20 tpi (I've checked with
a thread gauge). Under certain light I can almost convince myself the
new ones have a different helix angle, but I have no tools to quantify
that parameter or thread angle.

Any comments appreciated,

Chip C
Toronto
 
Chip C wrote:
> I've read prior threads in this group that seem to indicate that
> 9/16"x20 pedal threads are really very standard, yet I still find that
> generic new pedals don't fit my old (probably mid-'70's) Raleigh
> Sports. They get about a half-turn in and that's it. I have three old
> sets of pedals (in five years I've broken three pedals, all on the same
> side; what's up with that?), two of them Raleigh-branded and one
> unbranded but "for Raleigh", and they all thread in very easily.
>
> They're all visibly the same diameter and all 20 tpi (I've checked with
> a thread gauge). Under certain light I can almost convince myself the
> new ones have a different helix angle, but I have no tools to quantify
> that parameter or thread angle.
>
> Any comments appreciated,
>
> Chip C
> Toronto
>

Hi Chip,
Sounds like a BSW vs. UNF situation. Pitch might be the same but
the Unified pedal threads aren't rounded. So, they try to 'dig' into
the radiused roots of the BSW threads.

Try this: http://www.enginehistory.org/british_fasteners.htm

or, http://www.timebus.co.uk/rlh/whitworth.htm

--
PJ
'89 auto coupe, '02 6-spd coupe
 
"Chip C" <[email protected]> wrote in message
news:[email protected]...
> I've read prior threads in this group that seem to indicate that
> 9/16"x20 pedal threads are really very standard, yet I still find that
> generic new pedals don't fit my old (probably mid-'70's) Raleigh
> Sports. They get about a half-turn in and that's it. I have three old
> sets of pedals (in five years I've broken three pedals, all on the same
> side; what's up with that?), two of them Raleigh-branded and one
> unbranded but "for Raleigh", and they all thread in very easily.
>
> They're all visibly the same diameter and all 20 tpi (I've checked with
> a thread gauge). Under certain light I can almost convince myself the
> new ones have a different helix angle, but I have no tools to quantify
> that parameter or thread angle.
>
> Any comments appreciated,
>
> Chip C
> Toronto
>


You might have to run a tap through the crank arms. You can buy a set of
inexpensive pedal taps but you may be better off taking your bike or the
crank arms to a LBS and have them do it for you.

Chas.
 
"Chip C" <[email protected]> wrote in message
news:[email protected]...
> I've read prior threads in this group that seem to indicate that
> 9/16"x20 pedal threads are really very standard, yet I still find that
> generic new pedals don't fit my old (probably mid-'70's) Raleigh
> Sports. They get about a half-turn in and that's it. I have three old
> sets of pedals (in five years I've broken three pedals, all on the same
> side; what's up with that?), two of them Raleigh-branded and one
> unbranded but "for Raleigh", and they all thread in very easily.
>
> They're all visibly the same diameter and all 20 tpi (I've checked with
> a thread gauge). Under certain light I can almost convince myself the
> new ones have a different helix angle, but I have no tools to quantify
> that parameter or thread angle.
>
> Any comments appreciated,
>
> Chip C
> Toronto
>

Chip

You know that one is a left hand and the other a right hand thread, right?
Are you trying to screw them into the wrong sides?

Regards,

Tom
 
Around 1973, I replaced the stock pedals on a Raleigh Sports
with quill pedals that allowed the use of toe clips and straps.
The threads didn't fit well at all, I had to crank (pun intended)
hard on the wrench to get them in. I had the impression that
the stock Raleigh cranks and pedals, although compatible with
each other (and nominally 9/16"x20tpi), weren't machined to
industry standard thread dimensions.

Tom Ace
 
Chip C wrote:
> I've read prior threads in this group that seem to indicate that
> 9/16"x20 pedal threads are really very standard, yet I still find that
> generic new pedals don't fit my old (probably mid-'70's) Raleigh
> Sports. They get about a half-turn in and that's it. I have three old
> sets of pedals (in five years I've broken three pedals, all on the same
> side; what's up with that?), two of them Raleigh-branded and one
> unbranded but "for Raleigh", and they all thread in very easily.
>
> They're all visibly the same diameter and all 20 tpi (I've checked with
> a thread gauge). Under certain light I can almost convince myself the
> new ones have a different helix angle, but I have no tools to quantify
> that parameter or thread angle.
>
> Any comments appreciated,
>
> Chip C
> Toronto


Go to a bike shop that has pedal taps, tap it out, bob's yer uncle...
 
"Qui si parla Campagnolo" <[email protected]> wrote in message
news:[email protected]...
>
> Chip C wrote:
>> I've read prior threads in this group that seem to indicate that
>> 9/16"x20 pedal threads are really very standard, yet I still find that
>> generic new pedals don't fit my old (probably mid-'70's) Raleigh
>> Sports. They get about a half-turn in and that's it. I have three old
>> sets of pedals (in five years I've broken three pedals, all on the same
>> side; what's up with that?), two of them Raleigh-branded and one
>> unbranded but "for Raleigh", and they all thread in very easily.
>>
>> They're all visibly the same diameter and all 20 tpi (I've checked with
>> a thread gauge). Under certain light I can almost convince myself the
>> new ones have a different helix angle, but I have no tools to quantify
>> that parameter or thread angle.
>>
>> Any comments appreciated,
>>
>> Chip C
>> Toronto


Not uncommon. I've had the same problem with TA Zephyr crank arms. Last one
I had, the right pedal went in smoothly, but the left crank arm pedal hole
had to be tapped.

Gary Jacobson
Rosendale, NY
 
"Chip C" <[email protected]> writes:

>I've read prior threads in this group that seem to indicate that
>9/16"x20 pedal threads are really very standard, yet I still find that
>generic new pedals don't fit my old (probably mid-'70's) Raleigh
>Sports.


This is not an uncommon problem, I find that my vintage MKS sylvan
pedals (at least 20 years old) don't fit my stronglight 93 cranks (30
years old) very well. They were extremely tight. I rechecked both
several times - both are BSC 9/16".

try a pedal tap, and/or make sure that you grease the pedal threads
and the crank threads as well. also, it helps to use a nice big 10"
crescent wrench for as long as possible (until the pedals get so close
to the cranks that they no longer fit !!)

- Don Gillies
San Diego, CA
 
On 9 Jan 2007 12:14:49 -0800, "Chip C" <[email protected]> may have
said:

>I've read prior threads in this group that seem to indicate that
>9/16"x20 pedal threads are really very standard, yet I still find that
>generic new pedals don't fit my old (probably mid-'70's) Raleigh
>Sports. They get about a half-turn in and that's it. I have three old
>sets of pedals (in five years I've broken three pedals, all on the same
>side; what's up with that?), two of them Raleigh-branded and one
>unbranded but "for Raleigh", and they all thread in very easily.
>
>They're all visibly the same diameter and all 20 tpi (I've checked with
>a thread gauge). Under certain light I can almost convince myself the
>new ones have a different helix angle, but I have no tools to quantify
>that parameter or thread angle.
>
>Any comments appreciated,


ISTR, many years ago, being told that the reason some pedals were
really tight going in was that the crank makers wanted to ensure that
there was no slop whatever in the threads, so that the pedals would be
less likely to wallow out the hole. It sounds like the kind of thing
that a stodgy bunch like Raleigh might have actually thought was a
good idea, so I guess there's a possibility that the statement had a
basis in truth.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.
 
"Chip C" <[email protected]> writes:
>> I've read prior threads in this group that seem to indicate that
>> 9/16"x20 pedal threads are really very standard, yet I still find that
>> generic new pedals don't fit my old (probably mid-'70's) Raleigh
>> Sports.


Donald Gillies wrote:
> This is not an uncommon problem, I find that my vintage MKS sylvan
> pedals (at least 20 years old) don't fit my stronglight 93 cranks (30
> years old) very well. They were extremely tight. I rechecked both
> several times - both are BSC 9/16".
>
> try a pedal tap, and/or make sure that you grease the pedal threads
> and the crank threads as well. also, it helps to use a nice big 10"
> crescent wrench for as long as possible (until the pedals get so close
> to the cranks that they no longer fit !!)


Yes, there is a LOT of variance in thread finish - visible if you have a
few pairs of pedals handy. Mid-70s Campagnolo 1037/1037a for example are
famous for being thick with chrome over what may or may not have been a
good thread. . .

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
 
> On 9 Jan 2007 12:14:49 -0800, "Chip C" <[email protected]> may have
> said:
>> I've read prior threads in this group that seem to indicate that
>> 9/16"x20 pedal threads are really very standard, yet I still find that
>> generic new pedals don't fit my old (probably mid-'70's) Raleigh
>> Sports. They get about a half-turn in and that's it. I have three old
>> sets of pedals (in five years I've broken three pedals, all on the same
>> side; what's up with that?), two of them Raleigh-branded and one
>> unbranded but "for Raleigh", and they all thread in very easily.
>>
>> They're all visibly the same diameter and all 20 tpi (I've checked with
>> a thread gauge). Under certain light I can almost convince myself the
>> new ones have a different helix angle, but I have no tools to quantify
>> that parameter or thread angle.


Werehatrack wrote:
> ISTR, many years ago, being told that the reason some pedals were
> really tight going in was that the crank makers wanted to ensure that
> there was no slop whatever in the threads, so that the pedals would be
> less likely to wallow out the hole. It sounds like the kind of thing
> that a stodgy bunch like Raleigh might have actually thought was a
> good idea, so I guess there's a possibility that the statement had a
> basis in truth.



Bike shop owners had to think quickly when facing obviously overplated
pedal threads. I've said that but I have no reason to believe it is true

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
 
On Tue, 09 Jan 2007 12:14:49 -0800, Chip C typed:

> I've read prior threads in this group that seem to indicate that
> 9/16"x20 pedal threads are really very standard, yet I still find that
> generic new pedals don't fit my old (probably mid-'70's) Raleigh
> Sports. They get about a half-turn in and that's it.


Hmmm, I thought that was the one part of a Raleigh that was standard. I
have a 30 y/o Sports only inches from the keyboard--I may have to check if
it takes regular pedals.

Even if it's a little off--you can just have your LBS tap the threads for
modern pedals and you're good to go.
 

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