The Chainlink

MDI - Meidai Bicycle Pumps: Do you have one and do you love it?

  I've stumbled on a topic which no one has posted and for which there is very little information elsewhere. There is no question people love their Silca, SKS, TopeakPark Tool, Lezyne, or other favorite brand pumps but let's lend a little focus to a defunct brand which sold many bike pumps to American consumers and which have served us well for years and years.  I'm doing some maintenance on mine, such as adjusting, cleaning, and installing replacement parts, so I felt inspired enough to document the process.

  MDI sold pumps under the Cyclepro name and that is what I have had since about 1994, and it's otherwise known as the Meidai Top Super.  Please note:  This also applies to MDI manufactured Schwinn and Rampar branded pumps!  The maximum pressure (on the gauge dial) for these pumps is 140 PSI, which is enough for everyone who has "clincher" tires, but I've pumped up tubeless Tufo tires to 180 PSI with it.  It has survived weekly or biweekly sessions of pumping up tires through thousands of miles on my various bikes.  I have never changed the pump washer or tube washer until now.  I haven't needed anything to maintain it, except a little lube, until now.  The cylinder walls are still thick and intact despite all of the fillings and refillings of my tires through the years.  It has put up with neglect in various basements, survived crashing to the floor countless times, and it has put up with my overwhelming zeal for cycling.

  Simply stated, my MDI/Meidai Top Super bicycle pump is a rock solid tank which just needs a little TLC to keep going.  Here are the components I'm considering this week to keep my pump in shape for the next 20 years:

  I am still hanging on to my old MDI thumb lock air chuck as it still works just fine.  Also, after rebuilding the head with a new valve washer and housing it works like it did when it was new, losing at the most 5 PSI when compared to a hand held gauge.  I've had an original brass SILCA Italian made classic style presta head in my tool box for many years and when attached to the MDI air chuck it works effortlessly.

  Bypassing a full overhaul, the easiest thing to do is simply replace the hose and hose barb and to maintain the original internal hose diameter - (as of 8/6/2017 I concede I've found the right tubing on McMaster Carr for $0.60 per foot) 3/16" ID 250 PSI tubing by the foot, 7/16" OD, Thermoid VALUFLEX/GS McMaster SKU 5304K42 with Oetiker hose clamps McMaster SKU 5435K12- makes the Silca 3/16" tube kit with clamps look like a bargain for one pump but expensive for two.  See the link below for the hose barb to make 3/16" hose work on your MDI - the original hose barb just isn't long enough for hose clamps to really keep the hose from falling off the pump. The original MDI hose only worked because a fitting was crimped to the end of the hose by a specially built machine at the factory in Japan.  Since this fitting is brass, be sure to use a little grease on the threads before screwing it into the pump base and be certain to keep the pump away from water or damp areas - if kept wet the brass fitting will seize and rust into the base and you won't be able to get it out or replace it. You may also be able to find this at your local hardware store, Menards, etc. Dynaflo 3/16" Hose x 1/8" Male NPT Brass Hose Barb, for up to 150 PSI applications, Fastenal SKU 69918, UNSPSC 40141734, comes in pack of 5, $3.80 per pack, $9.61 shipping.  Personally I moved to having both 3/16" and 1/4" hose and accessories on hand...but (as of 8/6/2017) I've also employed a method of attaching and detaching these with reliable, relative ease.

  MDI was forward thinking enough to allow their customers to easily access the pressure gauge dial face for adjustments.  Two screws are taken out and you are there.  With a small screwdriver (1/8" wide slotted head) and a Post-It note protecting the dial face one can gently pop off the needle and readjust it to zero.  There is no threading or retaining nut keeping the needle on, it's just a very solid friction fit like the minute hand on a clock.  I adjusted mine and it is reading PSI and Bars accurately as compared to my two tire gauges which I recently had calibrated by G.H. Meiser (under their amazing and wonderful lifetime warranty!).

  Thankfully Silca has the pump washer and lubricant that appears most appropriate for this maintenance project.  I'm quite certain it will work, but I'll repost when everything is installed.  I could keep going with the original MDI pump washer but I'd rather replace it now before it falls apart.

  As I said at the beginning of this article, my caveat about these pumps is of course that the company no longer exists.  However I am bolstered by my research.  G.H. Meiser in Posen, IL said they would take a look at it if I sent it in for service as well, but fortunately this is not necessary.  

Please let me know if you have any information or critique about this project.

Regards,

Matt M

"I'm sure there's a crying need for that."

- Mrs. Hudson, Sherlock, The Empty Hearse, 2014

(P.S. Several Ebay auctions are active for MDI/Meidai pumps. If you would like to investigate further also look for Rampar and Schwinn 1500.)


Please note that  I am not liable or responsible for any repair to any pump you may attempt as a result of the recommendations of this article.  You will be relying on your skills and expertise for your various projects.  Please be safe and take the necessary precautions that all of your pneumatic connections are secure for high pressure applications.

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It looks like, but I can't confirm it, that since Schwinn branded pumps were made by MDI this article applies to them as well.  Specifically the pumps I am seeing mentioned in general Google searches (I know...I haven't been to the library) are Schwinn 1500 (truly an MDI classic model), Schwinn Super G Deluxe, and possibly a few others.  So if you have a Japan made Schwinn pump it seems to make sense that you would be able to use the same parts as any MDI pump would need.

It's still possible to buy what looks like an almost identical design to the MDI original.  It's called the Sunlite Model M.  It has plastic thumb lock though and there is no telling if it's possible to replace the pump washer, clean the cylinder, or adjust the pressure gauge needle. Also, according to this Amazon review, I won't be able to depend on Sunlite completely for usable parts.  It appears that the hose barb threading is not compatible with my MDI.

There is one recent Amazon review stating that the Sunlite replacement hose is compatible with MDI / Cyclepro pumps from years ago but the plastic head assembly and short hose length do not give me any reason to consider this option.  I can't imagine purchasing the hose just to test it since it's unlikely to be as well constructed or as functional as any of the options I have recommended in this post.

Done.  I rebuilt the original MDI thumb lock air chuck with the one from the failed pump hose which partially launched me into this project.  My air chuck has the original brass hose barb and MDI branded lever but I scavenged identical housing and a new washer from the failed pump hose.  As it turns out, the rubber in the washer in my air chuck had worn out and that was why I was losing so much air when I released the lever.

So the pump pressure gauge is incredibly accurate or to two PSI within the pressure read with a separate gauge after inflation.  No air escapes the tubing or connections.  I can walk away when I'm in the middle of pumping up the tire, get a glass of water, come back, and continue pumping without losing air.

I ordered four feet of the 250 PSI Continental hose.  It's truly remarkable stuff.  A great thing about having four feet of hose is that the hose absorbs much of the twisting that happens when positioning the air chuck, ensuring that the hose connections remain solid.  Obviously having four feet of hose means that I can attach the air chuck without having to be right next to the bike or placing the tire valve in any set position.

Note that Rampar (as in Raleigh Rampar) branded pumps also apply to this discussion.

It seems I was anxious to improve upon this project.  Through trial and error, I found the JMF 1/4in x 1/8in Hose Barb Lead from ACE hardware somehow fit.  I was a little dismayed to find that I could have purchased 200 PSI hose from ACE Hardware by the foot if I had just looked hard enough (it is not listed on their online catalog).  The original hose barb was 7/16" in diameter or about 11mm, so the thread pitch was baffling.  I pursued the dilemma further and tried a 7/16"-20 bolt in the pump base and it almost fit.  I also tried a M12X1.5 bolt in the pump base and it was just slightly too large.  Oddly enough a standard brass hose barb fit and no searching or exotic parts were ever necessary.  I put some Phil Wood grease on the threads and tightened it down and everything worked beautifully with no air leaks.  You will notice in the photos that I put additional 1/2" hose clamps on to keep the connections stable.

Regarding corrosion of brass fittings in the steel pump base when in contact with moisture - I found some steel alternatives for the brass barb connection pump base which are pretty inexpensive - made in China of course - and from Amazon - and this doesn't mean I couldn't find them at the local hardware store -

For 3/16" hose in a pack of 5 at $6.99 with free shipping (follow this link). 

For 1/4" (6mm) hose at $2.06 each with free shipping (follow this link).

Considering that I listed the 1/4" hose Parker Hannefin steel barb before in the article which was $16.20 with shipping, this is an awesome deal.

As a final note to this article, I should say that the original MDI tubing was 3/16" or 4.7mm ID (inside diameter) with 7/16" OD or 11.1 mm (outside diameter).  So if you wanted to repair the pump hose completely to original MDI spec and reject the option of all the 1/4" air hose accessories available in the United States, then by all means use the SILCA Replacement hose with clamps (or equivalent 3/16" I.D. tubing).  I can't find 3/16" tubing online sold by the foot like I could with 1/4" tubing from MSC in Indiana and that makes SILCA looks like the only possible supplier.  

Bear in mind that the Oetiker clamps and Continental tubing were about $16.00 total with shipping from MSC or $4.00 less than SILCA's price for their tubing kit without shipping.  You might as well pick up the tubing with the clamps from MSC.  I haven't been able to find pinch clamps at any store in my neighborhood or otherwise.  If I wasn't so particular I could have bought the hose and some regular hose clamps at my hardware store and been done with the project very quickly......  Below is the schedule of parts for the project, how much they cost, and where to get them.  

My apologies for the numerous edits.  I have been away from my desk and actually hunting down parts in the store....I assure you this is now an excellent guide to restoring your MDI pump to health.

Have a look at this article on competing bicycle pump heads.  It's fun to look at, I think, but these can get pricey.  The Kuwahara Hirame pump heads (Yoko at $71.50 and Tate at $62.01) tend to inspire a great deal of praise among enthusiasts and I would perhaps consider purchasing one at some point.  I do think the Kuwahara Hirame pump heads are beautifully made.

While the hose barb I used is brass and may be subject to galvanic corrosion or rust when exposed to damp conditions over a long period of time, such as being stored in a damp basement, I'm not concerned.  If you were looking for a rust proof hose barb beyond the MDI original, the Parker Hannifin 4-2 B2HF-SS 316 stainless steel hose barb ($14.32 from Amazon) for 1/4" I.D. hose is available.

Silca Presta Head from my bag of tricks in which many things have been accumulated over the years and previous generations....I've purchased a new SILCA 242 Gasket which they say lasts five times longer than previous gaskets.

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