Pedal Shafts, Freewheels and Chain Tensioners




1  P E D A L   S H A F T S

Some mopeds with external pedal shafts, and separate pedal and motor chains, have one of the crank arms permanently attached to the shaft and sprocket. With those, to get a new sprocket-side arm you have to replace the shaft-with-arm.

Some mopeds with external pedal shafts, and separate pedal and motor chains, have no crank arms permanently attached to the shaft and sprocket. With those the sprocket-side arm can be replaced.

More on this parts topic, later…




2  F R E E W H E E L S

Some mopeds have one drive chain and some have two. Two-chain mopeds, with both a motor chain and a pedal chain, have freewheels, like most bicycles. The freewheel is the rear pedal sprocket that spins free and goes “click click click” in the reverse direction, but locks up solid in the forward direction. The freewheel allows the pedals to be stationary even when the rear wheel is moving forward. The moped brands with right-side freewheels are Puch, Peugeot, Motobecane, Batavus, Sparta (Foxi), Hercules (Sachs), Piaggio (Vespa), Honda (PA50), Kreidler, KTM (Foxi), Kynast, Flandria. There are two brands with left-side backward freewheels, Jawa and Benelli. All of the other moped brands do not have external freewheels, but instead have a freewheel mechanism inside the engine unit.

The freewheel screws on and tightens with pedaling. Once it is tight, a special tool is required to remove it. The tool fits into slots in the freewheel center. Some low-end modern single-speed bicycle freewheels do not have removal slots. Those cheap kinds can be removed by destroying the freewheel. To remove a freewheel destructively without a removal tool, the freewheel is first disassembled, where all the little balls and clickers fall out, and then the inner hub is unscrewed in a bench vise or with a pipe wrench.

Most freewheels go on the right side of the bike and thus have right-hand thread, but Jawa and Benelli ones go on the left side of the bike and have left-hand thread. 


16a generic 16T
by Sunlite
made in Taiwan

16b MB 16T #60483
by The Best Wheel
made in France

16c Hercules 16T
by Esjot
made in Germany

16d Sparta 16T
by Atom
made in France

16h Motobecane 16T
by Atom, #16057
made in France









18b Motobecane 18T
by The Best Wheel
#15244 French thread

18d left hand Jawa 18T
by Velo, says date 76-78
made in Czechoslovakia

18e generic 18T
by Sunlite









20a Motobecane 20T
by The Best Wheel
#14298 made in France

20c Kynast 20T
by Esjot
made in Germany

20e generic 20T
by Sunlite

23a Puch 23T
by Atom-Maillard
made in France










Original and Replacement Freewheels

no. freewheel make  country     bike make  part #  teeth    thread    price   original on

16a Sunlite xxxxxxx Taiwan xxx replacement  0000  16T  1.375″- 24  $15

16b The Best Wheel France xxxMotobecane 60483  16T  1.375″- 24  $25  Solex

16c Esjot  xxxxxxx Germany Hercules 9000300401 16T  1.375″- 24  N/A  Sachs Westlake (P1) 

16d Atom xxxxxxxx France xxx Sparta 00. 055051  16T  1.375″- 24  $25  Sparta Foxi
16d Atom   xxxxxxx France xxx Peugeot xxx39026  16T  1.375″- 24  $25  Peugeot (optional)
16d Atom xxxxxxxx France xxx Motobecane 16057  16T  1.375″-.24  $25  Motobecane 7

16e Ocean xxxxxxx Italy xxxxx Piaggio 000114531  16T  1.375″- 24  $25  Piaggio Ciao, Si early

18a Atom xxxxxxxx France xxx Peugeot 00017550  18T  1.375″- 24  N/A  Peugeot 102, 103
18a Atom xxxxxxxx France xxx Batavus 00049020  18T  1.375″- 24  $30  1976-77 Batavus VA

18b The Best Wheel France xxxMotobecane 15244  18T  M34.7-1.0  $50  70’s MB with MB hubs
18b J Moyne xxxxX France xxxMotobecane 15244  18T  M34.7-1.0  $50  Wards Riverside (AV88)
18b The Best Wheel France xxxMotobecane 15244  18T  M34.7-1.0  $50  50’s-60’s Motobecane

18c Ocean .xxxxxxx Italy .xxxx Piaggio 00 103631  18T  1.375″- 24  $25  Piaggio Bravo, Grande

18d Velo xxxxx Czechoslovakia  Jawa  xxxx070040  18T  M35 -1 LH   $35  1970-83 Jawa 28, 207

18e Sunlite xxxxxxx China x.xxxreplacement  0000 18T  1.375″- 24  $15 

18f The Best Wheel France x.xxxreplacement  0000 18T  M32 – 1.0  $13  unknown application

20a The Best Wheel France xxxMotobecane 14298  20T  1.375″- 24. N/A  70’s MB with Leleu hubs
20a The Best Wheel France xxxMotobecane 14298  20T  1.375″- 24. $20  1978-81 MB with mags

20b Atom   xxxxxxx France xxx Batavus 00049019  20T  1.375″- 24  $30  Batavus HS50,Starflite
20b Atom   xxxxxxx France xxx Peugeot 00000586  20T  1.375″- 24  $30  Peugeot (optional)

20c Esjot  xxxxxxxx Germany x Kynast  00000586   20T  1.375″- 24  $22  Flying Dutchman

20e Sunlite  xxxxxx China xxx xreplacement  0000  20T  1.375″- 24  $16

22a Atom  .xxxxxxx France  Honda 41210-148-000 22T  1.375″- 24  none Honda PA50

23a Atom  .xxxxxxx France xxx Puch  3492410230  23T  1.375″- 24  $20-$30 Puch (all models)

Freewheel threads: Like with pedal threads there is a common size and an uncommon size slightly smaller.

The common size is 1.375″ – 24, which equals 34.92 – 1.06 mm. Most modern bicycles worldwide have this ISO (International Standards Organization) standard freewheel thread type. 

The uncommon size is M34.7 – 1.00, which equals 34.70 – 1.00 mm. This “French” thread type is on vintage bicycles from France, Belgium, Spain or Switzerland, and on Motobecane mopeds with Motobecane-made hubs.

So the French freewheels are slightly smaller than the rest of the world, 34.7 instead of 34.9. That small amount does not matter as long as the bike is pedaled gently. But it does matter when the pedals are pushed very hard. Then the loose fitting threads on the wheel hub can strip out, a disaster.  

It is difficult to tell which thread type a hub has, by measuring the thread tops with a calipers. The 34.92 thread hubs measure 34.65 to 34.7. The 34.70 hubs measure 34.55 to 34.6. On some hubs the tops of the threads are worn down and measure less. So a standard thread might seem like a French thread type. Because of this, it is better to put away the calipers and use “feel”.

When the freewheel and hub have the same thread type, the freewheel screws on easy, yet has no looseness. Looseness is felt with fingertips pulling and pushing the freewheel center side to side. When a 34.92 freewheel is on a 34.7 hub, the center of the freewheel can move 0.22 mm.  Here is a video of that. That looseness or “wiggle” is felt. The same is true for any threaded thing. When a bolt fits a nut, it screws on easy and yet does not wiggle.    

All of the freewheels in Myrons Mopeds inventory were measured by feel. For each bike model listed above, a sample rear wheel with original freewheel was measured directly by feel. The freewheel was removed. It’s threads were checked by screwing onto both a French and a standard hub. The wheel threads were checked by screwing on both a French and a standard freewheel.

Gauntlet of test wheels: MB 40, Batavus M48, Peugeot 103, Model 7 hub, MB 50, MB 50, MB 50VLA.
Not shown, Puch wheels and hubs, Sparta, Peugeot 102 hub, Kreidler, Sachs, KTM, Kynast, others.

Result: None of the hubs or freewheels had French thread, except Motobecanes with Motobecane-made hubs. Wow!

1970’s Puch & Motobecane 80mm hubs
L, Leleu-made Puch hub, standard thread
R, Motobecane-made hub, French thread

These are actual Motobecane rear wheels from Myrons inventory. All except one came from Los Angeles area bikes.

model xx rim x hub xx freewheel xxx teeth  thread
40XXxxX thin   MB xx  none xxxxxxxx 18T   French
40XXxxX thin   MB xx  none xxxxxxxx 18T   French
50XXxxX wide  MB xx  none xxxxxxxx 18T   French
50XXxxX wide  MB xx  none xxxxxxxx 18T   French
50XXxxX wide  MB xx The Best Wheel 18T   French
Model 7X 16″  Leleu x  none xxxx x xx xxx  standard
50VXxxX wide Leleu x  none xxxx x xx xxx  standard
50VXxxX wide Leleu x The Best Wheel 20T  standard
50VXXxx wide Leleu x The Best Wheel 20T  standard
50VLAxx mag  silver x The Best Wheel 20T  standard
LeMoped mag  gold xx  none xxxxx xx xxx  standard
LeMoped mag  gold xx The Best Wheel 20T  standard

Result: All Leleu-made hubs have standard freewheel thread 1.375″-24, even those for Motobecane. All Motobecane-made hubs have French thread M34.7-1.0. All Motobecane-made “6-star” mag wheels have standard thread, but it is tapered and begins with French thread, so that either type of freewheel can be used.

1975 Motobecane 50S
with MB-made hubs

1978 Motobecane 50V
with Leleu-made hubs


How to tell: The best way to tell if a 1970’s Motobecane moped rear hub is Motobecane-made (and therefore French thread) is visually. There is an prominent M logo on the freewheel side. There is no step on the freewheel side, instead it slopes gradually. The flanges go farther out from the spoke holes. So from 100 feet away, viewed from the side, the Motobecane-made hubs appear larger than Leleu-made hubs.



All two-chain rear hubs or wheels, on mopeds from the 1970’s and 80’s, have standard freewheel threads, except Motobecane-made hubs on 1950’s -60’s and some 1970’s Motobecane mopeds.

A standard thread freewheel fits a French thread hub and works fine when pedaled normally. Only when a strong athletic person pedals very hard, the hub threads can strip off, requiring wheel or hub replacement. 


Motobecane 100mm hubs
are also French thread

1950’s – 60’s Motobecane: Many models, maybe all, had French freewheel threads M34.7-1.0. In the 1960’s the parts manuals specified the thread. One example, shown at right, is for Motobecane AV88 and Motoconfort AU88. It lists the 18-tooth 15244 freewheel as having M34.7-100 thread. 

The French freewheel thread cover up: It is very odd that, after 1976-77, Motobecane had two different freewheel threads, but they hid that fact. Instead they made the teeth different, 15244 (French thread) was 18 teeth, and the newer 14298 (standard thread) was 20 teeth. The Motobecane America parts manuals list both freewheels without explanation. There does not seem to be anything about freewheels in the Parts or Service Bulletins. The physical freewheels do not say the thread. The actual parts labels do not say the thread either. As a result, this cover-up has caused confusion and mystery for 39 years (1978-2017).


3  P E D A L   C H A I N S



4  P E D A L   C H A I N   T E N S I O N E R S


Honda PA50

fig qty  price    Honda#
06  2  none  40234-148-000 pedal shaft bushing
09  1  $10.0 40535-197-600 pedal chain #410 80 link
10  1  none  40540-148-670 tensioner assy
11  2  $6.00 40541-148-010 roller wheel
27  1  $1.50 90581-831-650 washer 6 x 18
28  1  $0.60 92101-06012    hex bolt 6 x 12





P E D A L   S H A F T   B U S H I N G S

16.0 x 20.0 x 19.9 no lip  $2.50 Tomos 200166, special bronze

16.2 x 20.1 x 19.0 w/ lip  $5.00 Puch 349.142.0051, white plastic, for Maxi

16.2 x 21.0 x 15.9 w/ lip  $5.00 Vespa 102875, black plastic, for Ciao

16.1 x 21.2 x 16.5 w/ lip  $6.00 Batavus? , black plastic

16.1 x 21.3 x 18.7 w/ lip  $5.00 Buzzetti 0168, black plastic, for Puch Magnum

16.2 x 25.6 x 15.5 w/ lip  $5.00 Vespa 141737, black plastic, for Bravo, Grande, Si