Mike Mill’s "Legend" Frames.

And the copies.

And a bit about the man himself...

A truly Forward thinking Design Engineer...



Mike Mills Photo Courtesy Phil Hyde

Reading through the Mike Mills section on the Otter website and wondered if you would be interested in a photo of Mike taken at Hungry Hill. From memory, this was late nineties at the start of the Old Codgers trial.


I knew Mike through motor sports. He was a regular at Greeves trials in the South-West on a Greeves borrowed from Dave Bignold. As we know he went on to build his special BSA. A truly great guy and engineer...

Kind regards


Phil Hyde...


Photo Courtesy Simon Chell.


This is Simon's Genuine Mike Mills framed machine.




Photo Courtesy "Hammertight".

Chris Chell and Mike Bowers sit proudly on their Mike Mills "Legend" BSA B25's.  

12/04 /2016.


Mike Mills Prototype BSA B25.


Photo. Mike Mills Prototype BSA B25, 250...


OK I have had so much interest in this frame over the past few months. That I thought I better do a page on the Mike Mills "Legend" machines..

Yes it is Good? How do I know?

Well I have a frame built on this jig by the late John Husband (Hubbo)? John borrowed the jig for a while when Mike got ill, and constructed four or five frames from the jig. Roger Taylor did the welding.

I have the frame from the bike that belonged to Nick Draper, the one he rode to win the Year 2000 Manx Classic trial on.

Nick told me that the frames were identical to Mike's frame except for a tweak in the steering head angle that made them even better.

 You can judge for yourself if you think this is true.

What I can say about this frame is that it was designed by a designer with one hell of a lot of skill.

 A man that was wasted at an organization such has BSA, with their backward thinking, that everything they used had to be made to a price, and not the best that they could achieve.

 Mike showed a metalsmith’s skill. Using only the minimum of periphery tube to achieve a beautiful and simplistic design, to achieve the functions of the entire concept.

 Using the top and down tube to carry the engine oil with the front tube also acting as a cooler was a stroke of genius.

This also distributed the oil weight evenly over the entire sprung weight.

Simplicity was the keynote only using bends in the tubes where necessary.

And using a steel box to connect the engine to the swinging arm thus making this unit one, and not relying on the flexing of  the frame... Another stroke of forward thinking and engineering skills.

The frames were built using racing car specification T45 tubing, and of the correct dimensions, for the job.

Triumph/BSA four-stud forks were elected has Mike had so much input into their development at their later stage. 

He also designed a stealth style alloy fuel tank has was befitting to the design of the entire bike.

 All in all Mike Mills, was a designer that BSA overlooked as they ran out of time, what a waste, that we lost this generation of re-thinkers.


Photo Courtesy Lee Prescott.


This is Mike's bike as it was at the 2006 Sam Cooper Union Jack Trial.


Note, that these machines were designed to use Ohlins rear suspension units.

Well Mike after leaving CCM, worked there developing suspension for amongst others Yamaha, who then bought into Ohlins and were part of that company until Kneth Ohlin bought the shares back from Yamaha not long ago.

Mike developed the upside-down forks amongst other things to make the yokes stiffer for the GB bikes that were now using Ohlin forks.

You can still buy "Twin-shocks from Ohlin" to get your build correct. most of the bikes on this page have these Yellow rear shocks fitted.



The late Mike Mills here riding "The-Legend", that this frame and complete trials machine has become...


Photo Courtesy "Hammertight".

Above Chris Chell rides one of the last genuine MM "Legend" frames these were supplied by Mike "Bonkey" Bowers. Who bought the last stock from Mike when he became Ill. This photo was taken at the BMCA trial at Gaerstone Shrop's on 10/04/2016.


Photo Courtesy Mike Bowers

A super shot of the Chris Chell MM "Legend" machine...





This is the finished Dave Dawson bike ready to go to its new owner, WOW. This too has the B25 engine bottom end but is fitted with a C15 cylinder head and special barrel by Pete Kirby.



Photo Courtesy Tracy Jupp...

Here is the ex Chris Denney "Legend" machine with Tank and exhaust system built by,

Steve Gagg, bike now owned by Tracy Jupp...


Photo Courtesy Tracy Jupp..

And the other side, Note: the shaved down B25 cylinder head and barrel...



Here is the Chell's machine at the Red Marley trial, I think this  bike is the ex Mike Mills machine that is sometimes ridden by Mike Bowers...


Photo "Hammertight'...

This "Legend" machine was built by Gerry Minchell and the engine is the last TR25 engine to come out of the Triumph factory and was the  Bob Hains engine...



"Hubbo"Mike Mills Copy frame with,

"Cotswold" engines...


Photo "Otterman"

This is my "Hubbo" MM frame with Cotswold engine.

And more photos below with detail.



It is the pivoting of the back engine mounting to the swinging arm that is interesting. This links the engine straight to the drive train supporting the twist from the engines power...



The "Hubbo" MM frame was said to have a slightly different head angle than Mike's frames.

And some say a slightly shorter stance.

 But I have no idea if that is the case, there may be slight differences from one jig to another, so that would be the only difference and of course, the way the frames are welded together makes the most difference, some operators are better than others at welding, and this shows in the final product...

But we all know that the original Mike Mills frame that any jig has been taken from is just a copy of the superb design that this frame is...




Photo Courtesy Andy Pitt.


The bike above used to belong to Andy Pitt, before he had to sell it on, with regret so he tells me.

This is a genuine Mike Mills built frame.


And the one below is the bike the Dawson Boys  Pete and Dave built, using one of the last batch of frames that Mike ever built.


Thanks guy's we know it could only be yours by the quality of the build, probably the last Mike Mills frame to be put into service too


Photo Courtesy Dave Dawson.


This frame is said to be from the last "Mike Mill's" batch.


Photo Courtesy Andy Morgan.

The frame above is one of a batch of copy Mike Mills Legend frames that Andy Morgan commissioned...

And very nice it looks too, but this frame will have come from a jig taken from one of the genuine MM frames.


Roger Taylor RTS.

I have found out his week,

July 5th 2013.

That Roger Taylor from RTS, made the batch of "Hubbo" frames, out of T45 tubing, and these were slightly smaller, and not so tall has the Mike Mills frame, also with revised steering head angle. So I was right with my assumption?


There has been a replica of Mike's frames  made in Yorkshire, to modern day dimensions, and another in Shropshire ,"Metal Malarki", so I am told but I have never seen one in flesh so to speak.


Visiting my tube supplier, and showing him my frame, he says a frame made of his speedway frame spec tubing may be a better bet.

He also criticised the gussets and  mounting plates, saying these should be made from the same material and spec as the frame tubes! Which when you think about it is so true.

We also checked the gauge of the tubing of my frame, which was said to be 18 and 22, but found out that most was 16 and 17 gauge and the front tube slightly thicker.

I still think if you want a frame to last it should be 16 gauge for most of the tubing, and to soften the ride of the frame the joints should be Sif-Bronze welded, which we agreed, and can be  done with a Oxy-Acetylene torch or a DC Tig welder at 35 amps..


 Well it looks like we have located the frame jig that my Hubbo frame was built on and the guy who now has it is going to build a batch of frames from it, 6 or even 8 was mentioned.

I will give you more details later !

 Meanwhile I have been told of this bike, that is for sale, interested then mail me and I will get details.

 I have set my jig up to build one of these frames for a very old friend of mine when the "CT140 Otter Mini" is finished.

 And my frame jig below.


Photo of "Ottermans Jig "Courtesy Otterman.


I hope to make at least one spare frame from this for myself later, so that at at least my "Legend " lives on.


Photo Courtesy Dave Langston.


Here is a photo of the last "Works" BSA to come out of the Factory.

"Mike Mills" built this frame and tuned the engine, It was owned by Dave Langston...

But now is in the ownership of The "Squire" of Stratford Upon Avon, Alan Wright.

Not quite: the bike is now been passed on by Wrighty. And is secure in the BSA collection, of my very good friend Ted Freeman.

There will better photos and information on this machine and others in Ted's collection later. Worth waiting for.


Ray Battersby's Story about Mike Mills.

Ray Battersby,

Worked with MIKE MILLS.

Here is his story.

"MIKE Mills".


I'm a very late arrival at your Mick Mills seance but I'm not one for social media and forums.


I worked with MIKE Mills at The Austin at Longbridge between c1972 and 1976. He was always known as MIKE there.


He initially worked on the Petrol Engine Design section of around 20-25 designers in the Engineering Block. Petrol engines were split into four teams (A-Series, B-Series, E-Series and F-Series). F-Series was a brand new SOHC engine of around 1.5 litres but when Mike arrived, it was on its last legs as a viable design project. I worked in a sub-set of A-Series on the new H-Series SOHC and K-Series SOHC engines. Whilst they too looked like getting the chop, out of their ashes came the O-Series that did go into production. The SOHC concept used on all these engines was also tried on the B-Series which became known as the L-Series. Mike Mills was the only designer working on this L-Series project which instead of becoming a subset of B-Series, became attached to the still-born F-Series, hence Mike's boss was the rather grumpy Gordon Whitehead.


I believe that Mike arrived at Longbridge direct from Umberslade who had already supplied 2-3 other designers, one being Jeff Bishop who worked with me on engine designs and who worked on the P30c Bandit/Fury project at Umberslade.


The K-Series was abandoned around the end of 1972 and I successfully applied to join the 'Advanced' Engine Design team that were based in the Round House (also known as the 'Elephant House') at Longbridge. It's official name was the Styling Studio. Our projects were so secret (we were told) that we were discouraged from talking with our old pals in the 'ordinary' petrol engine designs department.

So I lost contact with Mike for a few weeks/months.

Then I found he had become the third member of our advanced team and I was on the next drawing board to Mike.

We all worked for Stan Johnson who was as deaf as a post, the third member of our 'advanced' team was John Rowe who had no motorcycle links.


I got to know Mike much better and he told me of his personal project at that time, designing a compact 500cc single cylinder four-stroke engine especially suitable for off-road competition work.

At lunchtimes, he'd roll back his work drawings to reveal the drawing of his own engine and we'd sit and eat our sandwiches discussing the technicalities.

It may even have been a pushrod single too - agh! Memory! Mike approached everything from first principles.

He'd ignore all that had been done before and simply consider what was wanted and what was the simplest/cheapest/fastest way of doing it.

He had a foolscap exercise book (we all had actually) full of our calculations and rudimentary COBOL computer programs but the difference between us was that Mike's books were full of motorcycle calculations.

His bibles were Volumes 1 and 2 of The Internal Combustion Engine in Theory and Practice by CF (Charles Fayette) Taylor and published by MIT. I guess he learned of these books from Jack Williams at Umberslade.


At this time Mike lived with his wife at 10, Roman Way, Alcester, Worcs and was an active trials competitor.

He was a very big friend of Mike 'Bonkey' Bowers too and thanks to your piece, I now know the origins of that friendship.

I once borrowed his own home-made three bike trailer and was amazed by its simplicity. I copied it and made one for myself.

A well-known trials rider called Chris Leighfield was on the engineering staff at Longbridge during Mike's time there (he eventually moved to Australia) and I recall that they were often chatting together.


I lost contact with Mike when I left Longbridge completely in January 1976 but in the four years that I knew him, I cannot recall Mike ever drawing or discussing a motorcycle chassis. It was always his engine.


Jeff Bishop wasn't a particular friend of Mike's despite both working at Umberslade. Indeed, Jeff used to annoy Mike by reminding him that he'd helped Jack Williams design the Ariel 3!

I don't know the truth behind this claim but it used to annoy/embarrass Mike!


But I have good memories of Mike, a big man with a gentle manner and a slight limp (never found out why) who would always explain things clearly.

It's a pity he's gone before I could reacquaint myself with him.


I  hope you learned something new from the above.


Cheers Ray.



Yes Ray we have, and it makes all my time spent on this site worth while when I receive "Gems" of information like this.

Thank you so much...

Regards Charlie.


Photo Ray Battersby.

Now in the Edward Freeman Collection.



Ray has just sent me a revamped picture of Mike's last Works BSA frame and also the Patent information for the rising rate rear suspension that Mike devised. I will put it on tomorrow.



There is so much more to say about this man the more you delve the more you get.

Mike had  a long list of patents in his name and things you would never dream about. The above is the "Swindon four bar swinging arm linkage system" that Mike invented and then every one including Yamaha used later...

I said he was a guy that was wasted when he was at BSA but it looks like he was wasted for most of his life. A truly un-sung Hero.



I Have this afternoon, just had a gem of an email arrive from the lovely lady Sue...

 I will let her tell the story, of this priceless machine.

 Note the suspension on this little bike and it was built nearly Fifty years ago...



Dear "Char7748" !


Mike Mills...


I hope you will not mind my emailing you, but I recently read on the internet an article from "The BSA Otter" about Mike (Mick) Mills - I had also seen previously a not dissimilar article in TMX News about Mike.


My husband and I knew Mike and his wife Mavis back in the days of the Witley Motorcycle Club - when Mike and my husband rode trails.  I am in fact still in touch with Mavis.


I thought you might be interested in the photograph of a bike  (Andrew's Special) that Mike made for my son Andrew (when he was probably 7 or 8) - and Andrew will be 50 this year !  which I have never had the heart to part with.


It is a weeny bit rusty in places and the tyres have perished !! - It would be interesting to hear what you think of this rather "special" bike.


With best wishes


Sue Storr - (previous name Sue James)...


Thank you so,much for the story Sue...




Just found this photo from Simon Chell of when he first built his Mike Mills framed BSA C15-C25.... This was one of the first batch of seven frames  that Mike Mills built...Could have been the first Simon says...

 And like Simon says, if you are thinking of fitting a B40 engine into a genuine MM frame you will struggle with getting it in because of the extra height of the engine...

Don't forget they were built by Mike to use a BSA B25 engine...



Much more later.

What A "Legend"...